Browse the evidence

Sarcopenia diagnosis requires both low muscle mass and weakness; low muscle mass alone is weakly or not associated with functional disability.

To accurately diagnose sarcopenia in older adults, you must measure both muscle mass and muscle strength. Relying on muscle mass alone will miss many individuals at risk for disability. Use standardized cutpoints: grip strength <26 kg for men and <16 kg for women, and appendicular lean mass adjusted for BMI <0.789 for men and <0.512 for women.

Habitual sleep duration of 9 hours or more per night is associated with a 30% increased risk of all-cause mortality compared to the reference range of 7-8 hours.

Aim for 7-8 hours of sleep per night. Sleeping consistently 9 hours or more is associated with a 30% higher risk of death. If you consistently need this much sleep, it may be a sign of underlying health issues worth investigating with a doctor.

Causal inference between short sleep and obesity is difficult due to lack of control for important confounders and inconsistent evidence of temporal sequence in prospective studies.

While short sleep is linked to obesity, we cannot yet say it causes it. Other factors like diet, activity, and stress may explain the link. However, given the consistency of the association, improving sleep is still a prudent health strategy.

Spending 9.5 or more hours per day sedentary is associated with a statistically significantly higher risk of death.

Avoid sitting for more than 9.5 hours a day. If you have a desk job, incorporate standing breaks and light movement throughout the day. The risk of death increases significantly once sedentary time exceeds this threshold, even if you exercise moderately.

Hypertension prevalence and mortality burden are significantly higher in low- and middle-income countries compared to high-income countries, with deaths attributable to high blood pressure increasing in Asia and sub-Saharan Africa.

Recognize that hypertension is a major killer in low- and middle-income countries. Support global health initiatives that scale up treatment coverage and improve community effectiveness in these regions.

Chronic low-grade inflammation (inflammaging) is a fundamental endogenous driver of aging, creating a vicious cycle with cellular senescence that leads to organ dysfunction and age-related diseases.

Aging is closely linked to chronic, low-grade inflammation. While this paper is a mechanistic review, the implication is that strategies reducing systemic inflammation may support healthy aging. Focus on lifestyle factors known to modulate inflammation, such as regular physical activity, adequate sleep, and a nutrient-dense diet, as these are foundational to managing 'inflammaging'.

Immunosenescence, characterized by a decline in immune cell function and an increase in pro-inflammatory cytokine secretion, impairs the clearance of senescent cells and pathogens, exacerbating aging.

Immune function declines with age, leading to increased susceptibility to infection and chronic inflammation. Maintaining immune health through vaccination, stress management, and nutrient adequacy is crucial for older adults.

For deaths related to mental/behavioral disorders, neurological conditions, and non-transport accidents, lower BMI (up to 24-27 kg/m²) is associated with increased mortality risk, showing an inverse linear association rather than a J-shape.

Don't assume being thin is always safer. For neurological and mental health-related causes of death, this study found that lower BMI (down to 24-27) was associated with higher risk. Maintaining a healthy weight (not underweight) is important for protecting against these specific outcomes.

Grip strength follows a life-course trajectory of increasing to a peak in early adulthood (males 29-39 years, females 26-42 years), maintaining through midlife, and declining thereafter, with significant gender differences emerging from adolescence.

Use grip strength as a vital sign that changes with age. Do not compare your current strength to your 20-year-old self or to the opposite sex. Instead, compare your measurement to age- and gender-specific centiles. A value below the 10th centile for your age/gender group may indicate 'weak grip' and warrants further clinical assessment for frailty or sarcopenia risk, especially if you are over 50.

Embryonic skeletal muscle formation is primarily driven by extrinsic morphogen gradients (Wnt, Shh, BMP) that pattern the somite and regulate intrinsic transcription factors (Pax3, MyoD, Myf5), whereas adult muscle regeneration relies on the activation of quiescent satellite cells that reuse this same genetic hierarchy.

Understanding muscle biology requires recognizing that muscle growth and repair are governed by complex genetic and signaling pathways. While resistance training stimulates these pathways, the underlying biological machinery for creating and maintaining muscle tissue is deeply rooted in developmental processes that remain active in adults via satellite cells.

Satellite cells are the essential progenitor cells for adult skeletal muscle regeneration, residing in a quiescent state within the niche until activated by injury or other stimuli to differentiate into new muscle fibers.

For long-term muscle health and repair, the activation of satellite cells is crucial. While resistance training is the primary stimulus, the biological reality is that these cells must be activated to contribute to muscle growth and repair.

The Generation R Study is a population-based prospective cohort study designed to identify early environmental and genetic causes of normal and abnormal growth, development, and health from fetal life until young adulthood.

This paper does not offer a specific intervention or diet. It describes a large-scale research study designed to understand how genetics, environment, and lifestyle factors from pregnancy onwards affect health. For an individual, this means that long-term health is influenced by a complex interplay of factors starting before birth, and that large-scale observational data is being gathered to understand these relationships.

NAD+ serves as a co-substrate for enzymes like sirtuins and PARPs, and as a nucleotide analog in DNA ligation, impacting energy metabolism, DNA repair, and gene expression.

Understanding NAD+ roles helps explain why lifestyle factors like exercise and diet are important for healthspan. NAD+ is not just for energy but also for DNA repair and gene regulation.

The mortality risk associated with high BMI is significantly attenuated in individuals aged 65 years or older, suggesting that strict weight control may be less critical for longevity in the elderly.

If you are over 65, you do not need to aggressively pursue a BMI below 25. This study found no increased mortality risk for those over 65 with a BMI above 25. Focus on overall health and function rather than strict weight loss, as being slightly heavier may not be harmful and could be protective.

Consuming an additional daily serving of unprocessed or processed red meat is associated with significantly increased risk of mortality, coronary heart disease, type II diabetes, stroke, and colorectal cancer, and has the highest environmental impact.

Limit or eliminate daily consumption of unprocessed and processed red meat. This is linked to higher risks of heart disease, diabetes, stroke, cancer, and early death, as well as the highest environmental impact. Replace with plant-based proteins like legumes, nuts, or whole grains.

Epigenetic clocks, particularly those tuned to phenotypic age or mortality risk (e.g., GrimAge), are robust biomarkers for predicting biological aging and adverse health outcomes.

Epigenetic clocks offer a promising way to measure biological age, potentially identifying those aging faster than their chronological age. This could guide personalized interventions to slow aging, though clinical application is still emerging.

Age-related muscle atrophy is primarily driven by the loss of muscle fibers and motor units starting around age 50, rather than just the shrinking of existing fibers, and this process is largely independent of physical activity levels.

Understanding that muscle loss is partly due to losing entire muscle fibers (not just shrinking them) helps explain why maintaining muscle mass becomes harder with age. While you can't easily replace lost fibers, you can maximize the size and function of the fibers you have through regular exercise.

Genetically predicted lower alcohol consumption is causally associated with a reduced risk of coronary heart disease and ischaemic stroke, refuting the observational hypothesis that light-to-moderate alcohol intake is cardioprotective.

Current observational advice suggesting light-to-moderate drinking protects the heart is likely incorrect. Genetic evidence indicates that reducing alcohol intake, even for those who drink moderately, lowers the risk of heart disease and stroke. The safest level of alcohol consumption for cardiovascular health is zero or minimal.

Accelerated biological aging of specific organs, measured via plasma proteomic signatures, significantly increases the risk of organ-specific diseases and all-cause mortality, independent of chronological age.

Your chronological age is not your biological destiny. This research shows that your organs age at different rates, and accelerated aging in specific organs (like the heart or brain) is a strong predictor of future disease and mortality, independent of how many birthdays you've had. While this specific test is not yet standard care, the key takeaway is that organ-specific health monitoring is crucial. Focus on maintaining the health of your most vulnerable organs through targeted lifestyle interventions, as organ-specific aging is a modifiable risk factor for major diseases like heart failure and Alzheimer's.

Obesity and type 2 diabetes share a pathogenesis involving nutrient excess, inflammation, and mitochondrial dysfunction, leading to insulin resistance and beta-cell failure.

Type 2 diabetes in obesity is driven by cellular stress from excess nutrients, causing inflammation and mitochondrial issues. Managing weight reduces this cellular stress, improving insulin sensitivity and beta-cell function.

Early quadriceps strength loss after total knee arthroplasty is predominantly caused by failure of voluntary muscle activation (neural inhibition) rather than muscle atrophy.

After knee replacement, your leg is weak not just because the muscle shrank, but because your brain is failing to fully recruit it. Since pain isn't the main reason for this 'shutdown,' simply waiting for pain to disappear won't fix your strength. You need active rehabilitation that specifically targets retraining your nervous system to fire the muscle fully, such as high-intensity contractions or neuromuscular electrical stimulation.

Chronic low-grade inflammation (inflammaging) acts as a bidirectional driver that exacerbates all other hallmarks of aging, creating a vicious cycle that accelerates biological aging and age-related diseases.

Chronic, low-grade inflammation is a central accelerator of aging. While not an intervention itself, understanding 'inflammaging' highlights the importance of lifestyle factors (diet, exercise) that modulate immune response and reduce this persistent inflammatory state, thereby potentially slowing the progression of age-related diseases.

Overtraining Syndrome (OTS) is diagnosed by excluding organic diseases and confounding factors (such as caloric restriction, iron deficiency, or infections) rather than by a single positive diagnostic marker, as no current test meets all diagnostic criteria.

If you are experiencing unexplained performance decline and fatigue, do not rely on a single blood test to diagnose 'overtraining.' Instead, work with a professional to systematically rule out other causes like illness, nutrient deficiencies (iron, magnesium), or caloric deficits. The diagnosis is made by excluding these factors and observing a prolonged maladaptation to training stress.

Dual-energy X-ray absorptiometry (DXA) is the preferred criterion measure for body composition assessment because it provides a multi-compartment model including bone mineral content, offering higher accuracy than two-compartment methods.

If you have access to DXA, use it for the most accurate baseline of bone, fat, and muscle. However, recognize that other methods like BIA or skinfolds are valid for tracking changes over time if DXA is not accessible.