Browse the evidence

There is an average decline in leisure-time physical activity from age 13 to 23, with the decline being significantly greater in males than in females.

Expect a drop in activity as you move from adolescence to adulthood, but do not accept it as inevitable. The average decline is steeper for men, so men need to be more proactive about maintaining habits. The key is to recognize this trend early and intervene, especially if you are an inactive male.

Adopting a diet with higher pro-inflammatory potential, as measured by the Dietary Inflammatory Index (DII), is directly associated with an increased risk of cardiovascular disease (CVD) events, including myocardial infarction, stroke, and cardiovascular death.

To lower your risk of heart attack or stroke, prioritize a diet that minimizes inflammation. This means eating more fruits, vegetables, whole grains, nuts, and olive oil (characteristic of a Mediterranean diet) while limiting processed meats, refined grains, and sugary beverages. You do not need to track a specific index; adopting these anti-inflammatory food patterns is the actionable step.

The increase in local muscle Insulin-like Growth Factor 1 (mIGF-1) and IGFBP-3 levels following resistance training provides a mechanistic explanation for muscle hypertrophy in rheumatoid arthritis, suggesting a link to rheumatoid cachexia.

This finding suggests that the muscle-building response in RA patients is driven by local growth factors (IGF-1) rather than just mechanical stress alone. It implies that treating the underlying hormonal deficiency (rheumatoid cachexia) might be key to restoring muscle.

Physical activity performed during youth confers lifelong benefits in cortical bone size and strength that persist even after cessation of activity, whereas benefits in bone mass are lost.

Encourage high-impact or loading physical activities during youth to maximize bone size and strength. These structural benefits persist lifelong, providing a protective buffer against fractures in old age, even if bone mass declines later. Focus on building a larger, stronger skeletal frame early in life.

Continuing physical activity (throwing) into old age reduces age-related cortical bone loss and maintains more bone strength benefits than ceasing activity, though it does not add to bone size benefits.

Maintain loading physical activities into old age to preserve bone strength and reduce structural decay. While you may not increase bone size further, continuing activity helps maintain the strength benefits gained in youth by preventing accelerated bone loss.

Extreme mountain ultra-marathons (approx. 166 km with significant elevation change) cause severe neuromuscular fatigue, including both central and peripheral components, with full recovery of maximal force capacity occurring within 9 to 16 days.

After completing an extreme mountain ultra-marathon (like the UTMB), expect significant muscle weakness and fatigue. Do not rush back into intense training. Most recovery happens within the first 9 days, but full neuromuscular function may take up to 16 days. Prioritize rest and light activity during this period.

Performing 60 minutes of moderate-intensity treadmill exercise induces significant circadian phase shifts in humans, with large phase delays occurring when exercise is performed between 7:00 pm and 10:00 pm, and large phase advances occurring when exercise is performed at 7:00 am or between 1:00 pm and 4:00 pm.

If you need to adjust your sleep schedule, time your 60-minute moderate exercise (where you can talk but not sing) strategically. To fall asleep earlier (phase advance), exercise between 7:00 am and 4:00 pm. To stay up later (phase delay), exercise between 7:00 pm and 10:00 pm. Avoid exercising around 4:00 pm or 2:00 am if you want to minimize shifts, as these times produce minimal effects.

Low dietary fiber intake leads to a reduction in gut microbiota diversity and promotes the degradation of host mucus, increasing susceptibility to inflammation and colitis.

Ensure adequate intake of diverse dietary fibers from whole plant sources to prevent the gut microbiota from degrading your intestinal mucus barrier, which protects against inflammation and disease.

Higher leisure-time physical activity is associated with lower plasma levels of obesity-related inflammatory markers (sTNF-R1, sTNF-R2, IL-6, CRP) and improved insulin sensitivity, but this association is largely mediated by lower body fat (BMI and leptin) rather than a direct anti-inflammatory effect of exercise itself.

If you want to lower inflammatory markers like CRP and IL-6, increasing your physical activity is effective, but the primary mechanism is likely the reduction of body fat (weight loss) that often accompanies activity. Simply exercising without changes in body composition may not significantly lower these specific markers compared to those who are less active but have similar body fat levels.

A low-calorie lacto-ovo vegetarian diet is more effective than a Mediterranean diet at reducing LDL cholesterol, while the Mediterranean diet is more effective at reducing triglycerides.

If your primary concern is high LDL cholesterol, a vegetarian diet (including eggs/dairy) may lower it more than a Mediterranean diet. However, if you struggle with high triglycerides, a Mediterranean diet may be more effective. Both diets improve overall cardiovascular risk.

Sibutramine (5-20 mg/day) produces significant weight loss and metabolic improvements in obese patients with controlled hypertension, but causes small, statistically significant increases in blood pressure and heart rate.

Sibutramine can help obese patients with controlled hypertension lose weight and improve metabolic markers, but it requires careful monitoring of blood pressure and heart rate. The benefits of weight loss generally outweigh the small increases in vital signs for this specific population.

A dissonance-based eating disorder prevention program significantly reduces thin-ideal internalization, body dissatisfaction, dieting, negative affect, and bulimic symptoms in high-risk young women compared to a measurement-only control, though a healthy weight management placebo control also yields similar reductions in secondary outcomes.

For young women concerned about body image, simply learning about healthy eating may not be enough to change behaviors. A program that actively challenges the 'thin ideal' through writing and role-play (dissonance-based intervention) can significantly reduce body dissatisfaction and bulimic symptoms. However, note that a healthy weight management program also showed benefits for dieting and mood, suggesting that active engagement in health behaviors is also valuable.

Consumption of Western diet components (hyperglycemic carbohydrates, milk/dairy, saturated/trans fats) promotes acne vulgaris by activating insulin/IGF-1 and mTORC1 signaling, which suppresses FoxO1 and upregulates lipogenic transcription factors (SREBP-1c, PPARγ), leading to hyperseborrhea and comedogenesis.

To reduce acne risk, prioritize a diet low in refined carbohydrates, milk, dairy protein supplements, and saturated/trans fats. Instead, focus on a paleolithic-like diet rich in vegetables and fish. Consider supplements with plant-derived mTORC1 inhibitors and omega-3 PUFAs to support skin health.

Peptide YY (PYY) is a satiety signal released from the gut after meals that inhibits food intake and promotes weight loss, with effects observed in both lean and obese humans.

PYY is a hormone released by the gut after eating, especially when lipids and carbohydrates are present in the lower intestine. It signals the brain to stop eating. While its effect is modest, it is a key natural mechanism for satiety that works even in obese individuals.

Ghrelin is the first gut hormone shown to stimulate food intake, and its levels peak before meals, acting as a hunger signal.

Ghrelin is a hormone that signals hunger to the brain. Its levels rise before meals, stimulating appetite and gastric emptying. Understanding this pre-meal hunger signal can help individuals anticipate and manage their food intake more effectively.

Diet-induced weight loss reduces postprandial levels of anorexigenic gut hormones (GLP-1, PYY, CCK), which increases appetite and promotes weight regain, whereas exercise training tends to increase or maintain these hormones, supporting satiety and weight maintenance.

If you lose weight through dieting, expect your hunger hormones (GLP-1, PYY) to drop, making you hungrier and increasing the risk of regaining weight. To counter this, incorporate regular exercise, which appears to help maintain or increase these satiety hormones, thereby supporting weight maintenance.

Obese individuals exhibit attenuated postprandial responses of satiety hormones (GLP-1, PYY) compared to lean individuals, which correlates with lower subjective fullness and potentially contributes to overconsumption.

Obese individuals may experience less fullness after meals due to blunted satiety hormone responses. This is a biological factor, not just a lack of willpower. Strategies that naturally boost these hormones (like high-protein/fat meals or exercise) may help.

Concurrent strength and endurance training interferes with maximal strength development when both modalities engage the same muscle groups, primarily due to antagonistic intracellular signaling where AMPK activation inhibits mTOR.

If your primary goal is maximizing strength, be aware that adding endurance training (like running or cycling) in the same session or on the same days can blunt your strength gains. This is due to conflicting signals in your muscle cells. To fix this, separate your strength and endurance sessions by at least 6-8 hours, or prioritize one modality on specific days.

Poor sleep quality is associated with increased longitudinal cortical atrophy in community-dwelling adults, particularly those over the age of 60.

Prioritize sleep quality as a critical component of brain health, especially as you age. Poor sleep is linked to brain shrinkage (atrophy) in key areas. Focus on improving sleep efficiency (time asleep vs. time in bed) rather than just duration. If you are over 60, this link is even stronger. Consult a sleep specialist if you have chronic sleep issues.

Skipping 30-minute relief breaks during work shifts significantly increases insomnia, acute and chronic fatigue, and post-traumatic stress symptoms among hospital nursing staff.

If you are a healthcare worker, prioritize taking your full 30-minute break during your shift. The data shows that skipping these breaks directly correlates with worse sleep, higher fatigue, and increased stress. Treat this break as a non-negotiable part of your job safety protocol, not an optional extra.

Exercise-induced PGC1α expression activates branched-chain amino acid (BCAA) metabolism, using BCAAs as an energy source in the TCA cycle, and increases the production of the myokine BAIBA.

During prolonged exercise, your muscles use BCAAs for energy. This process triggers the release of BAIBA, a molecule that helps improve metabolism in fat tissue and other organs. This highlights the systemic benefits of exercise beyond just muscle contraction.

Type 2 diabetes mellitus (T2DM) acts as an independent pathogenic factor for osteoarthritis (OA) progression and arthroplasty complications through mechanisms of oxidative stress, advanced glycation end-products (AGEs), and insulin resistance, separate from mechanical load.

If you have Type 2 Diabetes and joint pain, treating the diabetes is part of treating the arthritis. High blood sugar and insulin resistance actively damage joint tissue through inflammation and stiffness (AGEs), independent of how much you weigh. Optimize glucose control to potentially slow joint degradation.

Dual-energy X-ray absorptiometry (DXA) is the recommended clinical technique for assessing body composition (lean and fat mass) because it offers accuracy comparable to CT/MRI with significantly lower radiation exposure and cost.

Use DXA for accurate body composition tracking. It is safer and more accessible than CT/MRI for clinical purposes. Ensure standardized conditions (fasting, no exercise prior) for accurate results.

Fat Mass Index (FMI) and Android/Gynoid (AG) ratio provide superior obesity and cardiovascular risk assessment compared to BMI and waist-to-hip ratio by directly measuring adiposity and regional distribution.

Use DXA to get your Fat Mass Index (FMI) and Android/Gynoid (AG) ratio. These are better predictors of cardiovascular risk and metabolic health than BMI or waist circumference alone. An AG ratio >1 indicates higher visceral fat risk.