Study archive · page 15

Pooling 60 studies of healthy adults, higher physical activity, cardiorespiratory fitness and exercise were associated with greater global white matter volume and better local white matter integrity, with small positive effects overall.

⚠What it shows: Worth taking seriously but it is a link, not proof: pooled from 60 studies of healthy adults, most of which compared fitter people with less fit ones rather than changing anyone's routine, so cause and effect cannot be pinned down. The effects were also small at the global level.Meta-analysis · Brain Imaging Behav

A meta-analysis of four randomised trials found supervised resistance training significantly improved depressive symptoms in two of four pooled comparisons, with small to moderate effects, but half the trials showed no effect and results were highly inconsistent.

⚠What it shows: A hint, not a verdict: only four trials qualified, half of them found no effect at all, and the studies disagreed with each other so strongly that the pooled benefit is shaky. Bigger, better-designed trials are what the authors themselves call for.Meta-analysis · Int J Environ Res Public Health

Pooled results from 19 randomised trials found that exercise training reduces depression slightly and anxiety more substantially in people with musculoskeletal pain.

⚠What it shows: A trustworthy direction with a modest size: results pooled from 19 trials where people were assigned at random show exercise eases mood in people with muscle and joint pain, but the depression benefit was small and only just cleared the bar statistically. The anxiety benefit was clearly larger, though the estimates varied more.Meta-analysis · Neuropsychiatr

Pooled results from eight randomised trials in 554 cognitively healthy older adults found that supervised aerobic training did not significantly change hippocampal volume, even though it moderately improved cardiorespiratory fitness. Gains in fitness were not linked to changes in hippocampal volume.

⚠What it shows: A credible null but not the final word: results pooled from just eight supervised trials in 554 healthy older adults, and the authors themselves flag methodological weaknesses across the studies. It says nothing about memory performance or about people with cognitive decline.Meta-analysis · Geroscience

Curcumin supplementation significantly increased circulating adiponectin compared with placebo in a pooled analysis of 6 randomised trials covering 652 adults. The effect appeared larger in trials lasting 10 weeks or less.

⚠What it shows: Promising but far from settled: results pooled from just 6 trials in 652 adults, and the authors themselves say more studies are needed before firm conclusions. Whether a higher adiponectin reading translates into any real health benefit was not tested here.Meta-analysis · Diabetes Metab Syndr

In a randomised placebo-controlled trial of 276 adults aged 50 to 75 with subjective cognitive complaints, N-PEP-12 was associated with time-dependent improvements in attention across 180 days, with exploratory gains at 90 days, but there was no significant overall difference between treatment arms.

⚠What it shows: A weak signal so far: one trial in 276 adults aged 50 to 75 with self-reported memory gripes found no overall difference between the supplement and placebo, and the specific improvements came from exploratory comparisons that still need confirming.RCT · Nutrients

Pooling 13 randomised trials, whey protein supplementation lowered circulating triglycerides by a modest 0.11 mmol/l but had no effect on total cholesterol, LDL cholesterol or HDL cholesterol.

⚠What it shows: Solid as far as it goes: results pooled from 13 trials found only a small triglyceride dip and nothing else moved, and even that dip vanished in leaner people, at lower doses, or when participants were also exercising or cutting calories. One author works for a dairy company, so keep that in view when weighing the framing.Meta-analysis · Eur J Clin Nutr

A review pooling 19 trials in 570 adults with overweight or obesity linked HIIT to lower blood pressure, triglycerides, body weight and BMI and to higher HDL cholesterol, but rated the certainty of that evidence low to very low.

⚠What it shows: Encouraging rather than proven: pooled from 19 trials with only 570 people in total, the studies disagreed with each other a lot and the reviewers rated their own certainty low to very low. The hint that age changes the response comes from comparing trial averages, not individuals, so it proves nothing about any one person.Systematic review · Front Physiol

In a meta-analysis of 26 randomised trials with 784 overweight or obese participants, moderate-intensity continuous cardio improved cardiorespiratory fitness significantly more than sprint interval training, matched HIIT, and showed no difference from either on body fat percentage.

⚠What it shows: A credible check on the hype: results pooled from 26 trials with 784 people carrying extra weight found steady cardio beat sprint intervals for fitness and matched interval training everywhere else. It says nothing about which approach people enjoy or stick with over the long run.Meta-analysis · J Phys Act Health

Coronary calcium read from ordinary nongated chest CT scans predicted future heart events about as well as the dedicated gated scan in 2472 adults, and scores from the two scan types were almost perfectly correlated.

⚠What it shows: Convincing on prediction, silent on treatment: 2472 adults free of heart disease had both scan types on the same day and were then followed for events, so it shows the everyday scan forecasts risk, not that acting on the result saves lives.Study · Circulation

In pooled individual data from 9 randomised trials covering 1481 adults with cardiometabolic conditions such as diabetes, overweight or cardiovascular disease, wearable trackers increased activity by 1656 steps per day over a median of 12 weeks. Gains were larger in men, people over 50, White participants and those with fewer other conditions, and only face-to-face delivery of the tracker improved effectiveness.

⚠What it shows: Solid for who it studied: patient-level data pooled from 9 trials where people were assigned at random, covering 1481 adults with conditions like diabetes and heart disease. Only about half of the eligible trial data could be obtained, and healthy younger users may see different results.Meta-analysis · J Med Internet Res

Across 12 randomised trials with 1693 healthy adults, wearing an activity tracker was associated with a modest short-term increase in physical activity, but subgroup analyses showed no clear benefit for activity or weight reduction.

⚠What it shows: Solid as far as it goes: results pooled from 12 trials covering 1693 healthy adults found a modest bump in activity, but the trials averaged only 21.4 weeks and the closer subgroup checks showed no clear benefit, so nobody knows whether the effect lasts or shifts the scale.Meta-analysis · JMIR Mhealth Uhealth

Interventions built around consumer activity trackers increased physical activity by 2123 steps per day in pooled trials of people with chronic conditions such as type 2 diabetes, heart and lung disease, overweight and sedentary older age. They also modestly lowered systolic blood pressure, waist circumference and LDL cholesterol.

⚠What it shows: Strong pooled evidence from 35 trials where people were assigned at random, covering adults with type 2 diabetes, heart or lung disease, excess weight or inactive older age. The trackers came bundled with counselling, so the device alone may not deliver the same result, and the health marker shifts were small.Meta-analysis · Int J Behav Nutr Phys Act

Pooled data from 11 randomised trials in healthy older adults found resistance training raised serum IGF-1 by 17.34 ng/ml and improved leg press and bench press strength, though in subgroups the IGF-1 rise was significant only in women.

⚠What it shows: Reasonably solid for the strength gains: results pooled from 11 trials in healthy older people, though the hormone finding split oddly, holding up only in women. Why lifting moves IGF-1, and whether a modest rise matters for health, remains unexplained.Meta-analysis · Hormones (Athens)

Across 21 randomised trials in people with sarcopenic obesity, exercise or nutrition alone produced only limited gains, especially for muscle mass, while combining the two improved body fat, muscle mass, grip strength and walking speed together.

⚠What it shows: A dependable summary of a thin field: results pooled from 21 trials where people were assigned at random, in older adults carrying both low muscle and excess fat. Most individual improvements were small, and the trials mixed different programmes and durations, so the best specific recipe is still unclear.Meta-analysis · Age Ageing

A modelling study of 5834 Chilean adults estimated that high physical activity levels could prevent more than 22,000 new cases (64.6%) of five chronic diseases, including diabetes, stroke, ischaemic heart disease, and breast and colon cancer, while simply meeting the activity recommendation would prevent 6522 cases.

⚠What it shows: A statistical model rather than a real-world result: it combined survey answers from 5834 Chilean adults with disease rates and risk figures from earlier research, so the numbers show what is plausible, not what any programme actually achieved. Whether the estimates transfer beyond Chile is unknown.Meta-analysis · Public Health

Among 509,926 older Americans with no dementia diagnosis who had recently been admitted to a skilled-nursing facility, receiving at least one dose of the recombinant shingles vaccine was associated with a 4-year dementia risk of 18.8% versus 24.6% in the unvaccinated, 5.8 percentage points lower, roughly 24% lower in relative terms. This is an association rather than proof of protection, and the authors' own checks suggest some of the gap comes from differences between the groups.

⚠What it shows: Striking but not proof: researchers followed 509,926 people through Medicare and nursing home records rather than assigning the vaccine at random, so the vaccinated group may simply have been in better shape to begin with. Only 8843 of them were vaccinated, the vaccine's manufacturer funded the work, and the authors' own tests point to some leftover confounding.Study · Ann Intern Med

Pooling 10 randomised trials with 633 overweight or obese adults with type 2 diabetes, resistance training improved HbA1c, and the analysis pointed to an optimum near 3 sessions per week at 44% of one-rep max, 45 minutes per session, roughly 1,500 repetitions weekly, over 23 weeks.

⚠What it shows: Useful pointers rather than a prescription: results were pooled from just 10 trials with 633 mostly older adults, so the precise optimum figures carry wide uncertainty even though the overall direction, that lifting lowers HbA1c, is consistent.Systematic review · Front Physiol

Across 62 trials in 8952 adults with cardiometabolic conditions, behaviour-change programmes added 3287 steps per day versus usual care, and multi-component interventions were the only design to improve every measure of physical activity. Multi-component approaches also reduced HbA1c by 0.24%.

⚠What it shows: Solid pooled evidence from 62 trials in 8952 adults with conditions like type 2 diabetes and heart disease, though the studies disagreed with each other in places and evidence quality varied. It compares how programmes are designed, not whether exercise itself works.Meta-analysis · BMC Med

A meta-analysis of 23 randomised trials found resistance training improved body composition most in postmenopausal, overweight or sedentary women, cutting fat and increasing fat-free mass, while premenopausal, lean and already-active women saw fewer measurable changes.

⚠What it shows: Good news with a boundary: results pooled from 23 trials show lifting shifts fat and lean mass most clearly in women who are postmenopausal, carrying extra weight or sedentary. The trials varied in their programmes and groups, so this maps who responds most, not exactly how much any individual will change.Meta-analysis · J Sports Med Phys Fitness

In women with PCOS, pooled trial data show moderate-intensity steady cardio improved insulin resistance while HIIT boosted VO2max, and both intensities lowered fasting insulin and LDL cholesterol. Neither moved BMI, blood glucose, triglycerides or blood pressure.

⚠What it shows: Reasonably trustworthy but not final: results pooled from 23 trials in 1,192 women, with the certainty rated low to moderate and the studies disagreeing with each other on the fitness results. It cannot crown one intensity as best overall, only show they act on different markers.Meta-analysis · BMC Womens Health

In two large Swedish cohorts, women drinking three or more glasses of milk a day had nearly double the mortality rate of women drinking less than one glass, and higher milk intake brought no reduction in fracture risk in either sex.

⚠What it shows: Take it as a flag, not a verdict: 61,433 women and 45,339 men reported their own diets and were followed for up to two decades, but people already in poor health may drink differently, which is why the authors themselves urge a cautious reading.Cohort · BMJ

Pooling 19 studies of more than 4.5 million people found no significant overall association between long-term PM2.5 or PM10 exposure and venous blood clots; a modest PM2.5 association emerged only in sensitivity analyses limited to studies reporting exposure the same way.

⚠What it shows: Treat this as unsettled: the underlying studies followed people rather than testing anything on them, and while 19 studies of over 4.5 million people mostly showed no clear link, a modest association appeared only when analysts kept to studies that measured exposure the same way. The studies also disagreed with each other heavily, which is why the authors stop short of a firm conclusion.Study · Thromb Haemost

Reducing alcohol intake lowered systolic blood pressure by 3.31 mm Hg and diastolic by 2.04 mm Hg in a meta-analysis of 15 randomised trials with 2234 participants. The more people cut their drinking, the bigger the drop, and effects were larger in those starting with higher blood pressure.

⚠What it shows: About as solid as lifestyle evidence gets: results pooled from 15 trials in 2234 people where cutting alcohol was the only difference between groups. The biggest drops came in heavier drinkers with higher starting pressure, so light drinkers with normal readings have less to gain.Meta-analysis · Hypertension