This week in the science

1. Metabolic & GLP-1well supported · human dataAdded 6 September 2026

   Cardio after eating lowers blood sugar and insulin, fasted cardio does not

   Pooled results from 51 crossover studies in healthy adults show a single bout of continuous aerobic exercise lasting at least 30 minutes lowered insulin, raised glucagon, and lowered blood glucose only when performed after a meal, not in the fasted state.

   ⚠What it shows: Solid but with a wide spread: results pooled from 51 small studies in healthy adults, fewer than 400 people per outcome, and the studies disagreed with each other a lot, so the exact size of the drop is uncertain. The glucagon finding rests on just 5 studies and 47 people.Meta-analysis · Sports Med

   Full breakdown →Insulin sensitivity explained →Metabolic Fitness Index →The Effect of a Single Bout of Continuous Aerobic Exercise on Glucose, Insulin and Glucagon Concentrations Compared to Resting Conditions in Healthy Adults: A Systematic Review, Meta-Analysis and Meta-Regression. Sports Med 2021
2. Trainingpreliminary · human dataAdded 6 September 2026

   Weight training made older adults with muscle loss and obesity faster on their feet

   Results pooled from six randomised trials in 221 older adults with sarcopenic obesity found resistance training improved Timed Up and Go times by 2.23 seconds and Short Physical Performance Battery scores by 0.93 points, with no serious adverse events reported.

   ⚠What it shows: Promising but not settled: results pooled from just six trials totalling 221 people, and the reviewers themselves rated the certainty of the evidence low to very low. The gains were consistent across trials and attendance was high, which counts for something.Review · J Exerc Sci Fit

   Full breakdown →Sarcopenia explained →Effects of resistance training on balance-related physical performance in older adults with sarcopenic obesity: a systematic review and meta-analysis of randomized controlled trials. J Exerc Sci Fit 2026
3. Women's Healthpreliminary · human dataAdded 6 September 2026

   Exercise helps women's hearts, but science barely asks about menopause

   A systematic review of 14 randomised trials found that physical activity programmes improved at least one cardiorespiratory fitness or cardiovascular risk measure in women, yet only one trial actually compared premenopausal with postmenopausal women, and all but two trials were rated low methodological quality.

   ⚠What it shows: Treat this as a signal rather than settled science: a sweep of all the studies found 14 trials, all showing some benefit, but all except two were rated low quality and only one compared women before and after menopause, so menopause-specific effects remain largely untested.Systematic review · Menopause

   Full breakdown →VO₂max explained →VO2max Calculator →Physical activity on cardiorespiratory fitness and cardiovascular risk in premenopausal and postmenopausal women: a systematic review of randomized controlled trials. Menopause 2022
4. Tech & Wearableswell supported · human dataAdded 6 September 2026

   Fitness trackers really do shift weight, and longer use works better

   A meta-analysis of 19 randomised controlled trials found that wearable activity trackers used as physical activity interventions produced moderate, significant reductions in body weight and waist circumference and large reductions in BMI, with stronger effects in people with obesity or chronic disease and when used for 12 weeks or more. Each additional week of use was linked to a further body weight reduction of more than 0.37%.

   ⚠What it shows: One of the stronger findings in this space: results pooled from 19 trials where people were assigned trackers at random, though the biggest gains appeared in people with obesity or chronic disease, so leaner users may see smaller returns.Meta-analysis · Obes Rev

   Full breakdown →Energy balance explained →Steps to Calories Calculator →The effectiveness of wearable technologies as physical activity interventions in weight control: A systematic review and meta-analysis of randomized controlled trials. Obes Rev 2019
5. Sleepwell supported · human dataAdded 6 September 2026

   Insomnia shows up in the blood: higher cortisol and simmering inflammation

   Adults with insomnia showed markedly elevated circulating cortisol and raised inflammatory markers including IL-6, TNF-α, CRP, IL-1β, IL-2 and IFN-γ compared with healthy sleepers, in a meta-analysis pooling 32 studies of 4578 people with insomnia and 28382 controls. Neuropeptide Y was reduced, while several other markers including BDNF showed no difference.

   ⚠What it shows: A consistent pattern but not proof of cause: results pooled from 32 studies that compared people with insomnia against healthy sleepers rather than testing anything, so it cannot say whether poor sleep drives these blood changes or something else drives both.Meta-analysis · Front Immunol

   Full breakdown →Cortisol explained →Sleep Calculator →Biomarker evidence for the pathophysiological mechanisms of insomnia: a systematic review and meta-analysis. Front Immunol 2026
6. Skin & Glow-upwell supported · human dataAdded 6 September 2026

   The combined pill clears acne, and the brand matters less than you'd think

   In a Cochrane review of 25 randomised trials, combined oral contraceptive pills reduced facial acne lesion counts, severity grades and self-assessed acne compared with placebo, with few clear differences in effectiveness between pill types.

   ⚠What it shows: Strong evidence for the basic effect: results pooled from 25 trials where women were assigned treatments at random showed the pill beat placebo for acne, but comparisons between pill formulations rested on limited and sometimes conflicting data, and how the pill stacks up against other acne treatments is unknown.Meta-analysis · Cochrane Database Syst Rev

   Full breakdown →Combined oral contraceptive pills for treatment of acne. Cochrane Database Syst Rev 2009
7. Supplementswell supported · human dataAdded 6 September 2026

   Vitamin D worked for ageing muscle mainly as part of a protein and exercise package

   In pooled results from 9 trials in 1420 older adults with sarcopenia, combining vitamin D with protein supplementation and exercise clearly improved hand grip strength, while vitamin D on its own shortened chair-stand time but did not improve gait speed or muscle mass.

   ⚠What it shows: Reasonably solid as far as it goes: results pooled from 9 trials in 1420 older adults with age-related muscle loss. Many of the comparisons are indirect, drawn across trials rather than within them, so the winning combination has not been tested head to head in one large trial.Meta-analysis · Nutrients

   Full breakdown →Sarcopenia explained →Protein Intake Calculator →The Optimal Strategy of Vitamin D for Sarcopenia: A Network Meta-Analysis of Randomized Controlled Trials. Nutrients 2021
8. Sleeppreliminary · human dataAdded 6 September 2026

   Yoga, Pilates and mindfulness helped new and expectant mothers sleep better

   Pooled results from 13 randomised trials in 782 perinatal women suggest mind-body therapies such as mindfulness, Pilates and yoga improve sleep quality compared with controls, though the certainty of the evidence was rated low.

   ⚠What it shows: Encouraging but shaky: results pooled from 13 trials in 782 women during and after pregnancy showed better sleep scores, yet the studies disagreed strongly with each other. The reviewers themselves rated the overall evidence as low certainty.Meta-analysis · Front Public Health

   Full breakdown →Pittsburgh Sleep Quality Index (PSQI) explained →Sleep Calculator →Effects of mind-body therapies on sleep quality in perinatal women: a systematic review and meta-analysis of randomized controlled trials. Front Public Health 2026
9. Gut & Microbiomepreliminary · human dataAdded 6 September 2026

   Synbiotics improved blood sugar control in diabetes, but left LDL untouched

   Pooled results from seven randomised trials suggest synbiotic supplements improve fasting glucose, insulin levels, insulin resistance, triglycerides and total cholesterol in people with diabetes, but have no effect on LDL or HDL cholesterol.

   ⚠What it shows: Promising but thin: results pooled from just seven trials in people with diabetes, and several of the improvements only just cleared the bar for statistical significance. Different products and doses across the trials mean a couple of new studies could shift the picture.Meta-analysis · Probiotics Antimicrob Proteins

   Full breakdown →Insulin sensitivity explained →Metabolic Fitness Index →The Effects of Synbiotic Supplementation on Glucose Metabolism and Lipid Profiles in Patients with Diabetes: a Systematic Review and Meta-Analysis of Randomized Controlled Trials. Probiotics Antimicrob Proteins 2018
10. Mindwell supported · human dataAdded 5 September 2026

    A few months of exercise eased midlife anxiety; a year of it did not

    Pooled results from ten randomised trials in 1463 midlife and older women found that programmed exercise lasting 12 weeks to 4 months reduced mild-to-moderate anxiety symptoms, while longer programmes running 6 to 14 months showed no reduction at all.

    ⚠What it shows: Decent evidence with one wobble: results pooled from ten trials in 1463 midlife and older women, and the benefit for the shorter programmes only just cleared statistical significance. Why year-long programmes showed nothing is still unexplained.Meta-analysis · Climacteric

    Full breakdown →Heart Rate Zone Calculator →The effect of programmed exercise over anxiety symptoms in midlife and older women: a meta-analysis of randomized controlled trials. Climacteric 2018
11. Bones & Jointspreliminary · human dataAdded 5 September 2026

    Mood and fear predict lasting back pain better than how you move

    A pooled review of fifteen studies found that depression, distress and fear of movement predicted whether non-specific low back pain became persistent, while physical factors such as trunk movement showed limited and inconclusive evidence. The certainty of the evidence was rated low across the board.

    ⚠What it shows: Treat this as a strong lead rather than a verdict: a sweep of fifteen studies, one covering 15,778 people, found the psychological links, but the authors rate the certainty of evidence as low to very low throughout. It shows prediction, not proof that treating mood or fear prevents lasting pain.Meta-analysis · Eur J Pain

    Full breakdown →Back Pain →Physical, Psychophysical and Psychological Predictors of Persistent or Recurrent Non-Specific Low Back Pain: A Systematic Review and Meta-Analysis. Eur J Pain 2026
12. Mindpreliminary · human dataAdded 5 September 2026

    Mindfulness courses lower cortisol, not just how stressed you feel

    Across 39 trials with 2,059 participants, mindfulness-based stress reduction programmes lowered cortisol, and beat control conditions in head-to-head comparisons. The effect was modest and varied considerably between studies.

    ⚠What it shows: A solid overall signal: results pooled from 39 trials in 2,059 people show a real but modest drop in cortisol, clearest in properly controlled trials and smaller when mindfulness was compared against other active programmes. The studies disagreed with each other for reasons the analysis could not explain.Study · Health Psychol

    Full breakdown →Cortisol explained →Mindfulness-based stress reduction interventions and cortisol regulation: A systematic review and meta-analysis. Health Psychol 2026
13. Trainingpreliminary · human dataAdded 5 September 2026

    Blood flow restriction may damage muscle in week one but not over time

    A systematic review of 15 randomised controlled trials found mixed evidence on whether low-load lifting with blood flow restriction damages muscle: some trials suggest damage may occur within 1 week, longer-term studies found none, and the technique still delivered gains in muscle strength and size.

    ⚠What it shows: Treat this as an open question rather than a verdict: a sweep of all the trials found only 15 in healthy adults, and nearly half of them could not say either way whether the cuffs cause muscle damage. The reviewers themselves call for bigger trials before anyone can be confident.Systematic review · Clin Physiol Funct Imaging

    Full breakdown →DOMS explained →Training Volume Calculator →Effect of blood flow restriction with low-load exercise on muscle damage in healthy adults: A systematic review of randomized controlled trials. Clin Physiol Funct Imaging 2024
14. Supplementswell supported · human dataAdded 5 September 2026

    Probiotics barely shift immune markers in healthy adults

    A systematic review of 18 randomised controlled trials covering 819 healthy adults concluded that probiotic supplements have only a limited effect on circulating immune and inflammatory markers; 8 trials reported some changes, but the evidence was too inconsistent to size any effect.

    ⚠What it shows: A solid basis for scepticism: this sweep of all the trials in healthy adults, 819 people across 18 studies, found the results so inconsistent that they could not even be combined into a single estimate. It says nothing about people with illness, where probiotics may behave differently.Systematic review · J Acad Nutr Diet

    Full breakdown →Probiotics guide →Probiotic Supplementation Has a Limited Effect on Circulating Immune and Inflammatory Markers in Healthy Adults: A Systematic Review of Randomized Controlled Trials. J Acad Nutr Diet 2020
15. Environmentwell supported · human dataAdded 5 September 2026

    City air is quietly shaving millilitres off healthy lungs

    Pooled results from 23 studies link outdoor particulate air pollution with lower lung function in healthy adults: each 10 µg/m3 rise in short-term PM2.5 exposure was associated with a 7.02 mL drop in FEV1, and a 10 µg/m3 difference in long-term PM10 exposure with a 71.36 mL lower FEV1 overall.

    ⚠What it shows: Solid enough to take seriously: results pooled from 23 studies of healthy adults all point the same way. The studies followed people rather than testing on them, though, and for long-term exposure smoking and other habits could explain part of the effect.Meta-analysis · Occup Environ Med

    Full breakdown →Effect of outdoor particulate air pollution on FEV(1) in healthy adults: a systematic review and meta-analysis. Occup Environ Med 2019
16. Metabolic & GLP-1preliminary · human dataAdded 5 September 2026

    Next generation weight loss drugs leave the original GLP-1s behind

    In a network meta-analysis of 58 trials covering 24 214 adults with overweight or obesity but without diabetes, next generation incretin drugs outperformed conventional GLP-1 agonists for weight loss: retatrutide cut body weight by 22.10% versus placebo, tirzepatide by 19.28% and CagriSema by 17.32%.

    ⚠What it shows: Strong evidence overall, pooling 58 trials of 24 214 adults, but few of these drugs have been tested against each other directly, so the rankings rest partly on indirect comparisons. The tolerability findings, including more people stopping retatrutide and danuglipron, were rated low certainty.Study · BMJ Med

    Full breakdown →Energy balance explained →Calorie Deficit Calculator →Comparative efficacy and safety of glucagon-like peptide 1 based drugs for weight loss in adults with overweight or obesity without diabetes: network meta-analysis of randomised controlled trials. BMJ Med 2026
17. Mindpreliminary · human dataAdded 5 September 2026

    Most people miss their exercise goals, and prescribed targets fare worst

    Across 30 low risk of bias trials of physical activity programmes, most participants failed to achieve their activity goals at every timepoint, with failure rates between 57.9% and 77.0%, and achievement declined further over time. Goals people set themselves, or set collaboratively, were achieved more often than goals prescribed to them.

    ⚠What it shows: A thorough sweep of all the studies on this, pooling 89 trials of 10,219 people, with the main analysis limited to the 30 most trustworthy studies. It measures goal achievement inside structured programmes, so it may not describe targets you set entirely on your own.Review · Health Psychol Rev

    Full breakdown →The rates with which individuals fail versus achieve physical activity goals: a systematic review and meta-analysis of randomised controlled trials. Health Psychol Rev 2026
18. Bones & Jointspreliminary · human dataAdded 5 September 2026

    Muscle-zapping machines only help arthritic knees when paired with exercise

    Pooled across eight randomised trials, neuromuscular electrical stimulation did not reliably improve pain, disability, quadriceps strength or walking distance in knee osteoarthritis. Added to structured exercise, though, it reduced pain more than exercise alone.

    ⚠What it shows: Take the headline null seriously and the bright spots gently: only eight trials fed this pooled analysis, and the one clear functional gain came largely from a single study. The pain benefit alongside exercise looks the most credible use, not the device on its own.Study · Orthop Rev (Pavia)

    Full breakdown →Neuromuscular Electrical Stimulation for Knee Osteoarthritis: A Meta-analysis of Randomized Controlled Trials Evaluating Pain, Disability, Muscle Strength, and Functional Performance. Orthop Rev (Pavia) 2026
19. Cardiowell supported · human dataAdded 4 September 2026

    Your heart's risk during a hard workout is tiny, and regulars carry even less

    In apparently healthy adults, the risk of sudden cardiac death or a serious heart event during or immediately after exercise is extremely low, well below 0.01 per 10,000 participant hours, and the long-term health benefits of regular vigorous exercise outweigh that brief rise in risk.

    ⚠What it shows: Solid ground: a sweep of all the studies on this in apparently healthy adults, so the reassurance rests on a broad evidence base. The unresolved problem is that most exercise deaths involve hidden heart disease that had shown no sign of itself beforehand.Meta-analysis · Can J Cardiol

    Full breakdown →All-cause mortality explained →Heart Rate Zone Calculator →The Acute Risks of Exercise in Apparently Healthy Adults and Relevance for Prevention of Cardiovascular Events. Can J Cardiol 2016
20. Women's Healthwell supported · human dataAdded 4 September 2026

    Adding exercise to hormone therapy did not measurably boost bone density

    Pooling 6 controlled trials in 585 healthy women, adding exercise to hormone therapy produced no significant extra gain in bone mineral density at the spine or hip compared with hormone therapy alone, despite a small trend in favour of the combination.

    ⚠What it shows: Treat this as an open question rather than a closed case: results pooled from 6 trials covering 585 women showed a small trend favouring the combination that never reached significance. The trials used very different hormone doses and enrolled women in different hormonal states, which may have blurred any real effect.Meta-analysis · J Clin Endocrinol Metab

    Full breakdown →Bone density explained →Effects of Hormone Therapy and Exercise on Bone Mineral Density in Healthy Women-A Systematic Review and Meta-analysis. J Clin Endocrinol Metab 2022
21. Gut & Microbiomewell supported · human dataAdded 4 September 2026

    Probiotics nudge blood sugar down in people with diabetes

    Pooled results from 41 randomised trials in 2991 people with diabetes found probiotics and synbiotics modestly improved long-term blood sugar (HbA1c), fasting glucose and insulin levels. Supplements containing multiple species were particularly effective for HbA1c.

    ⚠What it shows: Solid enough to take seriously, but the benefit is modest rather than dramatic: results pooled from 41 trials in 2991 people with diabetes. The trials disagreed with each other a fair amount, and which strains work best is still unsettled.Meta-analysis · Clin Nutr

    Full breakdown →Insulin sensitivity explained →Probiotics and synbiotics for glycemic control in diabetes: A systematic review and meta-analysis of randomized controlled trials. Clin Nutr 2024
22. Women's Healthwell supported · human dataAdded 4 September 2026

    Exercise helps pregnant and new mums sleep better

    Pooled results from randomised trials in 998 pregnant and postpartum women found exercise improved sleep quality, sleep efficiency, sleep duration, time to fall asleep, insomnia and daytime tiredness, with medium to very large effects.

    ⚠What it shows: A consistent and sizeable benefit, but from a small evidence base: results pooled from trials in 998 pregnant and postpartum women across eight countries, and only seven of the ten included trials had data that could be combined.Meta-analysis · Behav Sleep Med

    Full breakdown →Sleep Calculator →Effectiveness of Exercise in Improving Sleep Outcomes among Perinatal Women: A Systematic Review and Meta-analysis of randomised Controlled Trials. Behav Sleep Med 2022
23. Tech & Wearableswell supported · human dataAdded 4 September 2026

    Your wearable can do more than track sleep, it can improve it

    A pooled analysis of 20 randomised trials in 1608 adults found sleep interventions delivered through wearables significantly reduced sleep disturbance and sleep-related impairment, and improved overnight breathing measures.

    ⚠What it shows: Promising but not yet decisive: results pooled from 20 trials in 1608 adults across nine countries, and the authors themselves say longer, more rigorous trials in a wider range of people are still needed before firm conclusions.Meta-analysis · Nurs Health Sci

    Full breakdown →Optimising Your Sleep Environment →Sleep Calculator →The effect of wearable-delivered sleep interventions on sleep outcomes among adults: A systematic review and meta-analysis of randomized controlled trials. Nurs Health Sci 2023
24. Sleeppreliminary · human dataAdded 4 September 2026

    Mindfulness helps shift nurses sleep, aromatherapy doesn't

    Pooled trial data found non-drug interventions significantly improved sleep quality in nurses working rotating shifts. Mindfulness programmes were beneficial, while aromatherapy showed no significant improvement.

    ⚠What it shows: A believable overall benefit but an untidy evidence base: results pooled from 11 trials of shift-working nurses, and the trials disagreed with each other a great deal, so the true size of the effect is uncertain. The clearest single message is that aromatherapy, one of the most popular options, did not show a significant benefit.Study · Occup Med (Lond)

    Full breakdown →Optimising Your Sleep Environment →Sleep Calculator →Non-pharmacological intervention for shift nurses' sleep: systematic review and meta-analysis. Occup Med (Lond) 2026
25. Women's Healthpreliminary · human dataAdded 3 September 2026

    Exercise still reshapes the body after menopause, whatever the programme

    Pooled results from 13 randomised trials in 694 postmenopausal women found structured exercise programmes reduced BMI by 0.87 kg/m2, lowered body fat percentage and trimmed waist-to-hip ratio by 0.03. Evidence on body image was too limited to draw any conclusion.

    ⚠What it shows: Strong for the fat and waistline results: pooled from 13 trials in 694 postmenopausal women, mostly at low risk of bias, and the findings agreed closely across trials for BMI and waist-to-hip ratio. The body image question is wide open, since only one study measured it before and after.Study · Menopause

    Full breakdown →Body-fat percentage explained →Body Fat Calculator →Effects of structured physical activity on body composition and body image perception in postmenopausal women: a systematic review and meta-analysis. Menopause 2026
26. Trainingpreliminary · human dataAdded 3 September 2026

    Only resistance training moved the needle for muscle loss hidden in obesity

    An umbrella review of meta-analyses in people with sarcopenic obesity found resistance training improved gait speed by 0.14 to 0.17 m/s and lower leg strength by 9.97 kg, while aerobic exercise, mixed exercise and calorie-restricted diets with protein supplementation showed no significant benefit; certainty of evidence was moderate to very low.

    ⚠What it shows: Treat this as a pointer rather than a verdict: it pulls together four earlier reviews whose trials covered between 30 and 225 people, and the authors rate the certainty of the evidence as moderate to very low. Resistance training's edge may partly reflect it being the most studied option.Systematic review · Curr Obes Rep

    Full breakdown →Sarcopenia explained →Strength Standards →Effects of Nutrition and Exercise Interventions on Persons with Sarcopenic Obesity: An Umbrella Review of Meta-Analyses of Randomised Controlled Trials. Curr Obes Rep 2023
27. Sleeppreliminary · human dataAdded 3 September 2026

    Exercise deepens sleep in sleep apnoea, but only past 12 weeks

    In a meta-analysis of six randomised trials with 236 people with obstructive sleep apnoea, exercise programmes lasting more than 12 weeks reduced lighter stage N2 sleep and increased deep stage N3 sleep, while total sleep time, sleep efficiency and time to fall asleep did not change.

    ⚠What it shows: Encouraging but far from settled: pooled results from six trials in 236 people, and the deep sleep shift only reached significance in programmes longer than 12 weeks or once heart disease patients were set aside.Meta-analysis · J Sci Med Sport

    Full breakdown →Slow-wave sleep explained →Sleep Calculator →The effects of exercise programs on sleep architecture in obstructive sleep apnea: a meta-analysis of randomized controlled trials. J Sci Med Sport 2024
28. Longevitywell supported · human dataAdded 3 September 2026

    Muscle up, waist down: exercise shifted both at once after 60

    Across seven randomised trials with 558 community-dwelling adults aged 60 and over with sarcopenic obesity, exercise alone or with dietary supplements increased grip strength by 1.30 kg, gait speed by 0.05 m/s and appendicular muscle mass by 0.40 kg, while cutting waist circumference by 1.40 cm and total fat mass by 1.77 kg.

    ⚠What it shows: A consistent signal with modest sizes: results pooled from seven trials in 558 older adults, and the gains, like 0.05 m/s of walking speed, are real but small. The authors still call for better-designed trials to work out which exercise or supplement mix does the work.Meta-analysis · Maturitas

    Full breakdown →Sarcopenia explained →Body Fat Calculator →Effect of exercise alone or combined with dietary supplements on anthropometric and physical performance measures in community-dwelling elderly people with sarcopenic obesity: A meta-analysis of randomized controlled trials. Maturitas 2018
29. Supplementspreliminary · human dataAdded 3 September 2026

    Vitamin C lowered blood pressure and long-term blood sugar in diabetes trials

    Pooled results from 28 trials in 1,574 adults with type 2 diabetes linked vitamin C supplementation to a 6.27 mmHg drop in systolic blood pressure and a 0.54% fall in HbA1c, but most trials were short and small, and the authors say it cannot yet be recommended as a therapy.

    ⚠What it shows: A lead, not a therapy: results pooled from 28 trials in 1,574 adults, but most ran under six months with fewer than 100 people each, and the blood sugar finding rests on very low certainty evidence.Meta-analysis · Diabetes Care

    Full breakdown →Insulin sensitivity explained →Metabolic Fitness Index →Effects of Vitamin C Supplementation on Glycemic Control and Cardiovascular Risk Factors in People With Type 2 Diabetes: A GRADE-Assessed Systematic Review and Meta-analysis of Randomized Controlled Trials. Diabetes Care 2021
30. Supplementspreliminary · human dataAdded 3 September 2026

    Fish oil grew muscle without a single workout in most trials that checked

    A systematic review of seven randomised trials in 192 sedentary or immobilised people found that five of the six studies measuring muscle size reported higher muscle volume and mass with omega-3 supplementation and no training at all, and both studies measuring muscle protein synthesis found a higher rate.

    ⚠What it shows: Early and small: a sweep of seven trials covering just 192 sedentary or immobilised people, so nobody knows whether the effect adds anything for people who actually train.Systematic review · Crit Rev Food Sci Nutr

    Full breakdown →Muscle protein synthesis explained →Protein Intake Calculator →Muscle hypertrophy induced by N-3 PUFA supplementation in absence of exercise: a systematic review of randomized controlled trials. Crit Rev Food Sci Nutr 2023
31. Metabolic & GLP-1well supported · human dataAdded 3 September 2026

    Weight-loss jabs show no link to suicidal behaviour across 25 trials

    Across 25 randomised controlled trials, people taking GLP-1 receptor agonists such as semaglutide and liraglutide showed no higher rates of suicidal behaviour than controls, and the null held for suicidal ideation, attempts and completed suicides alike.

    ⚠What it shows: About as reassuring as trial evidence gets: results pooled from 25 trials where people were assigned at random showed no rise in any form of suicidal behaviour, on any of the drugs, and the trials did not disagree with each other. Suicidal behaviour is rare, though, so very small effects in specific groups cannot be fully ruled out.Meta-analysis · J Diabetes

    Full breakdown →Metabolic syndrome explained →Impact of GLP-1 Receptor Agonists on Suicide Behavior: A Meta-Analysis Based on Randomized Controlled Trials. J Diabetes 2025
32. Women's Healthwell supported · human dataAdded 3 September 2026

    Testosterone improves postmenopausal sex lives; long-term safety is untested

    A systematic review of randomised placebo-controlled trials found testosterone therapy improves sexual function in postmenopausal women, with some studies also reporting higher bone mineral density and lower HDL cholesterol; long-term safety remains unclear.

    ⚠What it shows: The sexual function benefit rests on several trials where women were assigned at random to testosterone or placebo, so it deserves real weight, but this sweep of the studies is clear that long-term safety has not been established. The drop in protective HDL cholesterol seen in some studies is the other reason for caution.Systematic review · Clin Endocrinol (Oxf)

    Full breakdown →Testosterone explained →A systematic review of randomized controlled trials investigating the efficacy and safety of testosterone therapy for female sexual dysfunction in postmenopausal women. Clin Endocrinol (Oxf) 2019
33. Bones & Jointspreliminary · human dataAdded 3 September 2026

    Pilates eases chronic low back pain in women, and menopause does not blunt it

    In pooled randomised trials, Pilates produced large improvements in pain and everyday function for women with chronic low back pain, and postmenopausal women benefited as much as younger women.

    ⚠What it shows: Consistent benefit, but treat the size with care: pooled effects this large often shrink as bigger trials arrive, and the comparison groups ranged from doing nothing to other treatments, so some of the gain may reflect structured exercise of any kind. The review also does not report how many women took part overall.Study · J Back Musculoskelet Rehabil

    Full breakdown →Back Pain →Efficacy of Pilates on chronic low back pain in women: A systematic review and meta-analysis. J Back Musculoskelet Rehabil 2026
34. Trainingpreliminary · human dataAdded 3 September 2026

    Cuffs add nothing to heavy lifting: no extra strength, no extra size

    Pooled evidence from 8 long-term and 34 single-session studies in healthy adults suggests that adding blood flow restriction cuffs to heavy resistance training, meaning loads of at least 60% of maximal strength, does not further improve muscle strength or size compared with conventional heavy training, likely because the physiologic demands are comparable.

    ⚠What it shows: A believable null, but the authors themselves rate the certainty of the pooled evidence as very low: only 8 studies tracked actual strength and size adaptations, all in healthy adults. The single-session findings on effort and repetitions completed also disagreed with each other.Meta-analysis · J Strength Cond Res

    Full breakdown →Hypertrophy explained →One-Rep Max Calculator →Acute and Chronic Effects of High-Load Resistance Training With Blood Flow Restriction in Healthy Adults: A Systematic Review and Meta-Analysis. J Strength Cond Res 2026
35. Tech & Wearableswell supported · human dataAdded 3 September 2026

    Fitness trackers cut sitting time only when paired with online coaching

    In a pooled comparison of 12 randomised trials with 2957 healthy adults, wearables paired with online coaching and social media support significantly reduced total sedentary time, outperforming control conditions, traditional non-wearable interventions and wearables used alone; no wearable strategy significantly reduced prolonged unbroken sitting.

    ⚠What it shows: Reasonably convincing for total sitting time: results pooled from 12 trials in 2957 healthy adults consistently ranked a wearable plus online support as the best strategy. Very little research looked at long unbroken stretches of sitting, so that part of the question remains genuinely open.Meta-analysis · BMJ Open

    Full breakdown →Effects of using wearable devices on reducing sedentary time and prolonged sitting in healthy adults: a network meta-analysis. BMJ Open 2024
36. Women's Healthpreliminary · human dataAdded 3 September 2026

    Soy isoflavones plus exercise fail to move bone density after menopause

    Pooled results from 4 randomised trials in 609 postmenopausal women found that isoflavone supplements combined with exercise training did not significantly increase bone mineral density at any site measured, and the combination added nothing over exercise alone or isoflavones alone.

    ⚠What it shows: A believable null built on thin ground: results pooled from just 4 trials in 609 postmenopausal women, and the authors note the trials were small with some method problems. It cannot rule out small effects that bigger trials might detect.Meta-analysis · J Chin Med Assoc

    Full breakdown →Bone density explained →Isoflavone combined with exercise on bone mineral density in postmenopausal women: A systematic review and meta-analysis of randomized controlled trials. J Chin Med Assoc 2020
37. Nutritionwell supported · human dataAdded 3 September 2026

    Weight loss sticks better in a group, still down 2.56 kg at two years

    A meta-analysis of 47 randomised trials found that group-based diet and physical activity programmes helped overweight and obese adults lose 3.44 kg more than controls at 12 months, with 2.56 kg of advantage still present at 24 months; programmes explicitly targeting weight loss, and men-only groups providing feedback and dietary goals, were associated with greater effectiveness.

    ⚠What it shows: About as solid as weight-loss evidence gets: results pooled from 47 trials in overweight and obese adults show a clinically meaningful loss versus controls. The programmes varied hugely in design, though, so exactly which ingredients make one group work better than another is still unclear.Meta-analysis · Appl Psychol Health Well Being

    Full breakdown →Energy balance explained →Calorie Deficit Calculator →Group-Based Diet and Physical Activity Weight-Loss Interventions: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. Appl Psychol Health Well Being 2018
38. Sleeppreliminary · human dataAdded 3 September 2026

    A bad sleep score made people feel worse, and the score was fake

    When 63 people with insomnia were randomly given fabricated feedback about their previous night's sleep, those told their sleep efficiency had been poor reported more sleepiness and fatigue and less alert thinking by the evening than those told it had been good. Their scores on a basic reaction-time test and a measure of sleep-related attentional bias did not differ.

    ⚠What it shows: Suggestive rather than settled: one experiment in which 63 people with insomnia were randomly assigned a fake sleep score for a single day, so it says nothing about long-term tracker use or about people who sleep well. Everything that shifted was how participants rated themselves; their actual reaction-time performance barely moved.Study · J Sleep Res

    Full breakdown →Sham sleep feedback delivered via actigraphy biases daytime symptom reports in people with insomnia: Implications for insomnia disorder and wearable devices. J Sleep Res 2018
39. Bones & Jointspreliminary · human dataAdded 2 September 2026

    Strength training on isokinetic machines eases arthritic knees

    Across 46 randomised trials in 2,860 people with knee osteoarthritis, isokinetic strength training improved knee muscle strength, range of motion and knee function scores, and reduced pain and stiffness compared with control treatments.

    ⚠What it shows: Encouraging but shaky: results pooled from 46 trials in 2,860 people with knee osteoarthritis all pointed the same way, yet the review's own authors rated the underlying evidence as poor because the trials disagreed with each other and many gave imprecise results. Bigger, better trials are still needed before this counts as settled.Meta-analysis · J Orthop Surg Res

    Full breakdown →Range of motion explained →A meta-analysis of randomized controlled trials: evaluating the efficacy of isokinetic muscle strengthening training in improving knee osteoarthritis outcomes. J Orthop Surg Res 2025
40. Immunitynot supported · human dataAdded 2 September 2026

    Vitamin D fails to fend off coughs and colds in trials of 30,263 people

    A meta-analysis of 30 randomised trials with 30,263 participants found vitamin D supplementation had no significant effect on preventing acute respiratory infections. Apparent benefits from daily and short-term dosing disappeared when only the highest quality trials were analysed, and publication bias was detected.

    ⚠What it shows: A convincing null: pooling 30 trials covering 30,263 people found no overall protection against respiratory infections, and the hints of benefit from daily dosing vanished in the best-run studies. Signs that unflattering results went unpublished weaken even those hints further.Meta-analysis · Nutrients

    Full breakdown →Vitamin D explained →Efficacy of Vitamin D Supplements in Prevention of Acute Respiratory Infection: A Meta-Analysis for Randomized Controlled Trials. Nutrients 2022

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