Study archive · page 17

Pooled results from 21 randomised trials in 4,053 community-dwelling adults aged 60 and over found unsupervised home resistance training was safe and modestly improved lower-limb strength, sit-to-stand power and balance, but did not reduce falls or improve quality of life.

⚠What it shows: Encouraging but modest: results pooled from 21 trials of 4,053 older adults training at home with nobody supervising. Only about two thirds of sessions were completed on average, and the gains stopped at leg strength, rising from a chair and balance, with no effect on falls.Meta-analysis · Ageing Res Rev

In adults 65 and older, resistance training produced significant growth in whole-muscle size and muscle fibre area across 28 pooled trials, yet measures of leg lean mass did not change significantly.

⚠What it shows: Strong evidence: results pooled from 28 trials where older adults were assigned at random to supervised lifting or a control group. The growth effects were modest in size, and the lean mass scans widely used in ageing research missed changes that direct muscle measurements picked up.Meta-analysis · Exp Gerontol

Across 17 randomised trials in older adults, resistance training was linked with changes in the internal architecture of muscle, with reported improvements in thickness, fibre pennation angle and fascicle length, though the pooled effect was small and the evidence base thin.

⚠What it shows: An early signal rather than a settled result: a sweep of all the studies on this found 17 trials with 488 older participants, and the authors themselves warn that the small number of studies and disagreement between them limit the findings. The direction is encouraging; the size is uncertain.Meta-analysis · Arch Gerontol Geriatr

Pooled results from 17 studies show that lifting in low-oxygen conditions produced similar gains in muscle size and one-rep-max strength to lifting in normal air, though moderate loads of 60-80% 1RM with rests of at least 120 s tilted slightly in hypoxia's favour.

⚠What it shows: Treat the subgroup findings lightly: results pooled from 17 studies showed no clear overall advantage for low-oxygen training, and the authors themselves call for more standardised trials before firm conclusions can be drawn.Meta-analysis · Sci Rep

Pooled results from 40 randomised trials in 1,312 healthy women aged 18 to 35 show resistance training significantly improved muscle strength (1.2 SMD), lean mass (0.4 SMD), power and body fat percentage, and doing more sessions was linked to greater lean mass gains.

⚠What it shows: About as good as this evidence gets for young women: results pooled from 40 trials in 1,312 healthy women aged 18 to 35, though the programmes varied widely and the link between weekly volume and strength only approached statistical significance.Meta-analysis · J Strength Cond Res

Across 18 randomised trials in 1283 adults aged 50 and over, resistance training at 70% of one-rep max or above built significantly more leg strength than lighter training, with no difference in bone density gains, fall rates or adverse events between the two approaches.

⚠What it shows: Convincing for strength, less definitive for bone: results pooled from 18 trials in 1283 adults aged 50 and over. Training programmes varied a lot between studies, so the exact recipe behind the strength advantage is still fuzzy.Meta-analysis · Geriatr Gerontol Int

Across 19 randomised trials, resistance training lowered total cholesterol by 11.47 mg/dl, LDL cholesterol by 8.48 mg/dl and triglycerides by 6.61 mg/dl in postmenopausal women, with the largest effects in women starting with high cholesterol or obesity.

⚠What it shows: Strong evidence as these things go: results pooled from 19 trials where postmenopausal women were assigned at random to lift or not. The puzzle is that programmes shorter than 16 weeks showed bigger changes, and HDL, the so-called good cholesterol, slipped slightly in women with obesity.Meta-analysis · Eur J Obstet Gynecol Reprod Biol

In overweight or obese postmenopausal and older women, both lower and higher volume resistance training improved body fat, metabolic risk and inflammation compared with not training, but higher volumes produced larger improvements in blood glucose and C-reactive protein.

⚠What it shows: Take the direction seriously and the exact sizes lightly: results were pooled from 20 trials in overweight postmenopausal and older women, but the reviewers themselves rated the certainty of the evidence low to very low. Higher volume looked better for blood sugar and inflammation, not across every outcome.Meta-analysis · J Sport Health Sci

Pooled results from 48 randomised trials in 5282 pregnant women suggest exercise has a moderate overall effect on perinatal depression, working better as treatment than as prevention, and better before birth than after.

⚠What it shows: Broad but imperfect evidence: results pooled from 48 trials in 5282 pregnant women, yet most trials were not blinded and few tested any single exercise type, so the rankings between yoga, aerobic work and the rest are tentative.Meta-analysis · J Affect Disord

Pooling 22 studies, women with PCOS had 2.69 times the odds of Hashimoto thyroiditis compared with controls, and women with both conditions showed higher insulin resistance than women with PCOS alone. Cholesterol and triglycerides were similar with or without the thyroid condition.

⚠What it shows: A real pattern but not a cause: results pooled from 22 studies that compared groups of women rather than testing an intervention. It cannot say which condition drives the other, and the authors call for long follow-up studies before firmer conclusions.Meta-analysis · Front Endocrinol (Lausanne)

A systematic review of endurance exercise in older adults found caffeine, and protein combined with beta-alanine, showed performance benefits in both sexes. Sodium bicarbonate and HMB looked favourable in older women, while older men saw no benefit from sodium bicarbonate or ubiquinone.

⚠What it shows: Early signals only: a sweep of all the studies on this turned up just 8 trials in older adults, too few and too varied to pool into a single estimate, so the sex differences here are hints rather than firm conclusions. The authors themselves say supplement use should be matched to the individual.Systematic review · Int J Environ Res Public Health

A meta-analysis of 11 trials in 254 people found quercetin supplementation improved endurance capacity, covering VO2max and endurance performance, by roughly 2% over placebo. The authors rate the effect as between trivial and small.

⚠What it shows: About as settled as supplement evidence gets: results pooled from 11 trials in 254 people agree the benefit exists and agree it is tiny. Typical study courses ran around 11 days at 1000 mg per day, and neither fitness level nor blood quercetin levels changed the result.Meta-analysis · Med Sci Sports Exerc

Vitamin D supplementation produced no significant change in IGF-1, a growth factor tied to muscle, bone and ageing, in a meta-analysis of six randomised trials totalling 773 participants.

⚠What it shows: A fair verdict from results pooled across six trials with 773 people: no meaningful change in IGF-1 overall, and none in any subgroup. The trials disagreed with each other considerably, so a small effect in specific groups cannot be entirely ruled out.Meta-analysis · Complement Ther Med

Pooling 16 randomised trials, morning exercise showed no clear overall advantage over evening exercise for most sleep outcomes, though evening sessions were linked with more time awake after falling asleep, especially at higher intensities.

⚠What it shows: A solid verdict from results pooled across 16 trials where people were assigned at random: the review backs exercising at whichever time you can stick to. The one downside found for evening sessions leaned on smaller studies, so treat that part as tentative.Review · Sleep Med Rev

Digital cognitive behavioural therapy for insomnia reduced insomnia severity scores by 5.00 points versus control across 33 randomised trials, and the improvement was still present at 1-year follow-up. Face-to-face therapy did somewhat better, but within the margin regarded as comparable.

⚠What it shows: Strong evidence: results pooled from 33 trials in adults with insomnia, and the benefit persisted a full year. The studies disagreed with each other on the size of the effect, and most compared the therapy against waiting lists or usual care rather than a convincing placebo.Meta-analysis · Sleep Med

Pooled results from 16 randomised trials in 771 young people aged 12 to 25 found that physical activity produced a large reduction in depression symptoms compared with control conditions, and dropout was no higher than in the comparison groups. The reviewers rated the overall quality of the evidence as low.

⚠What it shows: Promising but not settled: results pooled from 16 trials in 771 young people showed a large benefit, yet the reviewers downgraded the evidence to low quality because of bias within the trials and suspected missing negative studies. The true size of the effect is uncertain, even if the direction looks right.Meta-analysis · Psychol Med

A meta-analysis of randomised trials in cognitively healthy older adults found exercise improved several thinking domains, and trials with a higher percentage of women showed larger executive function gains across aerobic, resistance and combined training. Combined aerobic and resistance training beat aerobic training alone for global cognition, episodic memory and word fluency.

⚠What it shows: Reliable for the overall brain benefit, softer on the sex angle: results were pooled from randomised trials in healthy older adults, but the women's advantage comes from comparing trials that happened to enrol more or fewer women, not from testing men against women directly. Treat the sex difference as a strong hint, not a verdict.Meta-analysis · Front Neuroendocrinol

Pooled data from randomised trials show intermittent fasting reduced body weight by 1.78 kg, fat mass by 1.26 kg and waist circumference by 1.19 cm versus control diets, with small improvements in blood pressure, fasting insulin, insulin resistance, total cholesterol and triglycerides. LDL, HDL and long-term blood sugar did not change.

⚠What it shows: Believable but modest: results pooled from randomised trials up to October 2020 show small, consistent improvements across weight, waist, blood pressure and blood fats. The authors themselves say longer and better designed trials are needed before firm conclusions.Systematic review · Front Nutr

In a network meta-analysis of 28 randomised trials in people with metabolic syndrome, combined aerobic and resistance training produced the largest reduction in the inflammatory marker CRP, and that finding held up as robust. Apparent reductions in TNF-α and IL-6 were far less reliable.

⚠What it shows: Trust the CRP finding, be wary of the rest: pooled from 28 trials, the CRP result was rated moderate certainty with no sign that negative studies went missing. For TNF-α and IL-6 the studies disagreed wildly, and there were signs unfavourable results never got published.Review · J Investig Med

A meta-analysis of 43 randomised trials in 2,483 people found intermittent fasting reduced weight, BMI, waist size and fat mass compared with no diet at all, while preserving lean mass. Against ordinary calorie restriction, though, fasting showed no advantage except a smaller waist.

⚠What it shows: Solid as diet evidence goes: results pooled from 43 trials in 2,483 people, with a typical study running about 3 months. The key finding is comparative: fasting beat no diet at all, but against plain calorie cutting it added nothing beyond a smaller waist.Systematic review · Front Nutr

A sweep of 28 studies found that resistance training of at least 4 weeks produced no or minimal change in heart rate variability and other measures of cardiac autonomic control in healthy people, while people with existing disease improved on several measures.

⚠What it shows: A reasonably trustworthy broad sweep, though the underlying evidence was rated only fair quality and mixed randomised trials with weaker designs. The improvements appeared only in people with existing disease, so healthy lifters should not expect their numbers to move.Meta-analysis · Clin Auton Res

Combining aerobic and resistance exercise lowered postmenopausal women's blood pressure by a statistically significant but tiny amount, 0.81 mmHg systolic and 0.62 mmHg diastolic, across 11 randomised trials. Arterial stiffness improved more noticeably, falling by 1.18 m/s on a pulse wave velocity measure.

⚠What it shows: A reliable direction with a modest size: results pooled from 11 trials in postmenopausal women found average blood pressure fell by less than a single point, so this is no substitute for treatment where treatment is needed. Some subgroups, such as women over 60 or those training 150 minutes or more per week, appeared to gain more.Meta-analysis · Exp Gerontol

A meta-analysis of 16 trials found fasting regimens significantly lowered both leptin and ghrelin, the hormone that drives hunger, in healthy, overweight and obese adults. Adiponectin rose only marginally and resistin did not change.

⚠What it shows: Encouraging rather than settled: results pooled from 16 trials in healthy, overweight and obese adults. Nobody has yet tested whether the hormone shifts last, and the rise in adiponectin fell short of clear significance.Meta-analysis · J Health Popul Nutr

A meta-analysis of 117 randomised trials covering 21,118 adults found mobile health interventions produced small to moderate increases in physical activity, and the gains in walking and moderate-to-vigorous activity were still detectable at follow-ups beyond 6 months, though smaller. Most included trials were rated at high risk of bias.

⚠What it shows: The direction looks real, the size does not: results pooled from 117 trials all point the same way, but most of those trials had weaknesses serious enough that the reviewers graded the overall evidence low quality. Effects also shrank as follow-up got longer.Meta-analysis · J Med Internet Res