Study archive · page 35

Adding neuromuscular electrical stimulation on top of strength training in older adults with declining function improved only cardiorespiratory capacity beyond training alone, and the review behind this found just 3 eligible trials with low-quality evidence.

⚠What it shows: Treat this as an open question rather than an answer: a sweep of all the studies on this turned up just 3 trials worth pooling, and the authors themselves rated the evidence quality as low. The one benefit that did show, better cardiorespiratory capacity, needs confirming in bigger trials.Meta-analysis · Clinics (Sao Paulo)

Resistance training gives healthy adult women large gains in upper and lower body strength and a medium-sized gain in muscle mass, according to the first meta-analysis to look exclusively at women, pooling 24 studies.

⚠What it shows: Reliable as an overall picture: results pooled from 24 studies of healthy women training anywhere from 4 weeks to 12 months. Research fields tend to publish their successes, and correcting for that shrank the lower body strength effect from large to medium, so the exact sizes are uncertain.Meta-analysis · Sports Med

In obese older adults on calorie-restricted diets, adding resistance training three times a week prevented 93.5% of the diet's lean mass loss while fat loss stayed essentially the same, according to a meta-analysis of six trials.

⚠What it shows: A consistent picture built on a thin base: results pooled from just six trials in obese older adults, with programmes running 12 to 24 weeks. Whether the same protection holds for younger or leaner dieters is untested here.Meta-analysis · Nutrients

Adding aerobic training to a strength programme does not compromise gains in muscle size or maximal strength, according to a meta-analysis of 43 studies in healthy adults. Explosive strength gains may be blunted, particularly when cardio and lifting happen in the same session.

⚠What it shows: About as solid as training evidence gets: results pooled from 43 studies in healthy adults, and the conclusion held regardless of age, training background or cardio type. The one genuine cost was explosive power, which dipped mainly when cardio and lifting shared a session.Meta-analysis · Sports Med

Providing legumes (average 86 g a day) to 1,938 adults across 24 randomised trials lowered total cholesterol by 0.23 mmol/L, LDL cholesterol by 0.16 mmol/L and fasting glucose by 0.18 mmol/L. Not one eligible trial measured gut microbiome outcomes.

⚠What it shows: Worth taking seriously: moderate-certainty results pooled from 24 trials in 1,938 adults, some with existing conditions. The improvements were modest, and no trial was long enough or designed to test the gut microbiome effects legumes are famous for.Meta-analysis · Eur J Nutr

Viscous soluble fibre lowered systolic blood pressure by 1.59 mmHg and diastolic by 0.39 mmHg at a median dose of 8.7 g per day in pooled trials. Of five fibre types tested, only psyllium significantly reduced systolic pressure on its own, by 2.39 mmHg.

⚠What it shows: A real but small effect: results pooled from 22 trials in 1,430 people over a median of seven weeks. The studies disagreed with each other considerably, so the exact size of the drop is uncertain.Meta-analysis · Nutr Metab Cardiovasc Dis

A network meta-analysis of 116 trials in 4,711 adults doing resistance training found protein taken after exercise was most effective for gaining muscle mass, protein at night was most effective for strength, and milk proteins were among the best types; no timing or type improved physical performance tests.

⚠What it shows: Solid for muscle and strength, but the rankings come mostly from indirect comparisons because trials rarely pitted one timing against another directly. It pools 116 trials in 4,711 adults doing resistance training, and the evidence was rated moderate certainty.Meta-analysis · Int J Sport Nutr Exerc Metab

Pooling seven controlled trials in 541 adults, plant-based dietary patterns were associated with C-reactive protein concentrations 1.13 mg/L lower than omnivorous diets, though the trials varied widely and certainty in the result was rated low.

⚠What it shows: Promising but not proven: results pooled from just seven trials with 541 people, and the studies disagreed with each other enough that the authors rate the certainty as low. The effect held after stripping out trials that also prescribed exercise, which strengthens the case that diet was doing the work.Meta-analysis · Nutr Metab Cardiovasc Dis

Across 31 randomised trials, combined exercise ranked as the most effective of five exercise types for improving sleep quality in perimenopausal and postmenopausal women, with flexibility exercise second; the best-ranked types also improved quality of life.

⚠What it shows: Encouraging but not the final word: results pooled from 31 trials in menopausal women, with certainty rated only low to moderate depending on exercise type. The rankings rely partly on indirect comparisons, since most trials never tested the exercise types against each other.Meta-analysis · Climacteric

A meta-analysis of 15 randomised trials in 1,110 middle-aged women found aerobic exercise significantly reduced waist circumference and blood glucose and significantly increased VO2 max.

⚠What it shows: Reasonably solid: results pooled from 15 trials with 1,110 middle-aged women taking part all pointed the same way on waist size, blood sugar and fitness. The abstract gives no figures for how large the changes were, and insulin and blood fats are not reported as improved.Meta-analysis · Health Care Women Int

A systematic review of 25 randomised trials found exercise and health education might help manage perimenopausal symptoms, but methodological inconsistencies mean evidence-based lifestyle guidelines remain out of reach. Notably, not a single trial exclusively tested a diet-based intervention.

⚠What it shows: Treat this as a map of the evidence rather than a verdict: a sweep of 25 randomised trials that varied so much in design and quality that firm conclusions were impossible. The clearest finding is the gap, since no study tested diet on its own.Systematic review · J Aging Phys Act

Exercise reduced the risk of depression both during and after pregnancy in a meta-analysis of 32 trials with 4,189 participants, with yoga-style mind-body exercise working best before birth and structured aerobic exercise most effective for treating postnatal depression.

⚠What it shows: Strong enough to take seriously: results pooled from 32 trials in 4,189 people across pregnancy and the postnatal period. Effects looked smaller when exercise was compared against active alternatives like health education rather than against nothing at all.Meta-analysis · BMC Pregnancy Childbirth

Pooled results from six trials covering 76 healthy adults found molecular hydrogen supplementation did not significantly reduce exercise-induced oxidative stress compared with placebo, although it modestly improved antioxidant potential capacity, most clearly around intermittent exercise.

⚠What it shows: Take this seriously but lightly: results pooled from six small trials with just 76 people between them, using different doses, timings and delivery forms. The authors themselves call for more rigorous studies before anyone banks on the antioxidant bump.Systematic review · Front Nutr

A Cochrane review of nine trials in 622 overweight or obese adults found chromium picolinate produced an average extra weight loss of just 1.1 kg after 12 to 16 weeks, and the authors concluded there is no reliable evidence to support it as a slimming aid.

⚠What it shows: Treat this as a reason for scepticism: results pooled from nine trials in 622 overweight or obese adults showed only about a kilogram of extra loss, and the reviewers rated the evidence low quality. Safety reporting was so patchy that no firm conclusions could be drawn there either.Meta-analysis · Cochrane Database Syst Rev

Across six randomised trials of 1246 overweight or obese adults with metabolic syndrome, 6 to 12 months of diet and physical activity change reduced waist circumference by 3.12 cm on average and lowered the inflammatory markers C-reactive protein and IL-6, while raising adiponectin.

⚠What it shows: A consistent direction of travel: results pooled from six trials in 1246 adults with metabolic syndrome, all lasting 6 to 12 months, favoured lifestyle change on every marker measured. The authors still want higher-quality studies before the inflammation findings are treated as settled.Meta-analysis · Biol Res Nurs

In a 36-week mid-stage trial of 230 adults with obesity or overweight, the once-daily oral GLP-1 pill aleniglipron produced up to 11.3% more weight loss than placebo, with mostly mild to moderate gut side effects.

⚠What it shows: Promising but not final: one 36-week trial in 230 adults, run and part-authored by the drug's developer, so the result needs confirming in the larger late-stage trials that decide whether a medicine gets approved.Study · Nat Med

Across 12 pooled studies, people with midportion Achilles tendinopathy showed an immediate large reduction in tendon volume after isometric exercise, while healthy Achilles tendons kept their volume after acute loading.

⚠What it shows: Interesting but early: results pooled from 12 small studies of healthy and painful Achilles tendons, and several of the changes did not reach statistical significance. Whether a shrinking tendon means anything for pain or recovery is still unknown.Meta-analysis · J Biomech

Oral collagen supplements improved both pain and function in people with knee osteoarthritis across 11 randomised trials totalling 870 participants, with pain scores improving by 13.63 points more than placebo and function by 6.46 points, improvements the authors call statistically and clinically noteworthy.

⚠What it shows: Reasonably strong for a supplement: results pooled from 11 trials in 870 people with knee osteoarthritis all pointed the same way, favouring collagen over placebo. The trials disagreed with each other on how large the benefit is, so the exact size remains uncertain.Meta-analysis · Clin Exp Rheumatol

Across six randomised trials in 164 healthy older adults, exercise improved muscle mitochondrial quality, density, dynamics, oxidative capacity and antioxidant capacity. Resistance training was most tied to gains in mitochondrial density and dynamics, endurance training to antioxidant capacity.

⚠What it shows: An early signal rather than a settled answer: just six small trials covering 164 healthy older adults, and only one was rated good quality. The differences between training types need confirming before anyone builds a programme on them.Systematic review · Aging Clin Exp Res

In a network meta-analysis of 270 randomised trials with 15,827 participants, every exercise mode lowered resting blood pressure, but isometric training led the rankings with reductions of 8.24/4.00 mm Hg; the isometric wall squat and running were the most effective single exercises for systolic and diastolic pressure respectively.

⚠What it shows: About as strong as exercise evidence gets: results pooled from 270 trials covering 15,827 people, all with proper no-exercise control groups. The rankings compare modes across trials rather than head to head in the same study, so the ordering is a best estimate rather than a race everyone ran together.Meta-analysis · Br J Sports Med

Physical activity improved cognition in sedentary older adults across seven randomised trials totalling 321 people, with aerobic exercise and programmes longer than 12 weeks showing the clearest effects.

⚠What it shows: Promising but thin: results pooled from only seven small trials totalling 321 sedentary older adults, and the authors themselves call for more rigorous studies. The trials also disagreed with each other about how large the benefit really is.Meta-analysis · J Alzheimers Dis

Probiotic supplements had a modest but statistically significant effect on symptoms of depression, anxiety and stress in healthy working adults across 12 randomised trials of 3,350 people, and were linked to lower cortisol. A marker of systemic inflammation did not change.

⚠What it shows: Promising but not settled: results pooled from 12 trials in 3,350 healthy employed adults found only a modest effect. The trials used different strains, doses and durations, so nobody yet knows which probiotics actually help.Meta-analysis · BMC Psychol

In a systematic review of 39 randomised trials in adults with overweight or obesity, greater digital self-monitoring was linked to weight loss in 74% of the analyses that examined it, yet few interventions kept people tracking on at least 75% of days.

⚠What it shows: Convincing on consistency, weaker on cause: a sweep of 39 trials in adults with overweight or obesity found tracking and weight loss moving together, but it cannot prove the logging itself did the work. The real-world catch is that few programmes kept people tracking on most days.Systematic review · Obesity (Silver Spring)

In a meta-analysis of 62 studies, people with alcohol abuse or dependence showed moderate impairment across 11 of 12 cognitive domains in the first month of abstinence, deficits that persisted through the first year of sobriety and generally abated after 1 year.

⚠What it shows: Reassuring on recovery, but it compared different groups of people at different stages of sobriety rather than following the same individuals over time. It pools 62 studies of people with alcohol abuse or dependence, so it says little about moderate drinkers.Meta-analysis · Addict Biol