Muscle is not vanity. It is metabolic real estate, a glucose sink, and one of the better predictors of how the second half of life goes. Here is the evidence and the minimum dose.
Every longevity conversation eventually reaches supplements, and almost none of them start where the effect sizes actually are. Resistance training is unglamorous, hard to sell and difficult to package, which is roughly why it is underrepresented in the discourse relative to how well it performs.
What muscle actually does
Skeletal muscle is the largest site of glucose disposal in the body. It is where most of the sugar from a meal ends up, and it takes it up through a route that does not depend on insulin doing the asking. More muscle, and more active muscle, means a bigger buffer. Muscle is also the reserve the body draws on during illness and hospitalisation, which is one reason low muscle mass predicts poor outcomes in older adults.
The grip strength finding
The most striking single result in this area comes from the PURE study, published in The Lancet in 2015. Leong and colleagues measured grip strength in roughly 140,000 adults across seventeen countries and followed them for four years. Grip strength was inversely associated with all-cause mortality and cardiovascular mortality, and in that dataset it was a stronger predictor of death than systolic blood pressure.
Grip strength is not magic. Nobody thinks squeezing a dynamometer harder makes you live longer. It is a cheap, reliable proxy for total muscular strength, and total muscular strength is tracking something real about how robust a body is. That is exactly why it is useful.
The timeline you are working against
Adults lose roughly 3 to 8 per cent of lean muscle mass per decade after the age of 30, and the rate accelerates after 60. Strength declines faster than mass, and power, which is strength expressed quickly, declines faster still. Power is what catches you when you trip, which is why it matters disproportionately at the far end of life.
None of this is inevitable at the rate it usually happens. Sarcopenia is substantially a disuse phenomenon layered on top of a biological one, and resistance training reverses a meaningful part of it at any age, including in people in their eighties and nineties.
The minimum effective dose
Smaller than the internet suggests. A 2022 meta-analysis by Momma and colleagues in the British Journal of Sports Medicine pooled prospective cohort studies and found that muscle-strengthening activity was associated with roughly a 10 to 17 per cent lower risk of all-cause mortality, cardiovascular disease and cancer, with the association strongest at around 30 to 60 minutes a week. Beyond that the curve flattened, and at very high volumes the association weakened.
Thirty to sixty minutes a week. Two sessions. That is the dose associated with most of the benefit.
Protein, without the noise
Morton and colleagues published a meta-analysis in the British Journal of Sports Medicine in 2018 covering 49 studies. Protein supplementation improved strength and lean mass gains from resistance training, and the benefit plateaued at roughly 1.6 grams per kilogram of body weight per day. Above that, no additional gain was detected. For an 80 kg person that is about 130 grams a day, spread across meals. Older adults may benefit from the higher end of the range, since the muscle-building response to protein blunts with age.
How to use this
- Two sessions a week covering a push, a pull, a squat or hinge, and a carry. That is the whole programme for most people.
- Progress the load. The adaptation comes from asking for more over time, not from the exercises being clever.
- Hit protein. Around 1.6 g per kg per day is the evidence-supported ceiling for training benefit, spread across the day rather than in one hit.
- Do not finish with a cold plunge. Cold immediately after lifting blunts the adaptation; see the contrast therapy guide.
This article is for educational purposes and is not medical advice. Talk to your doctor before starting any new protocol, especially if you have a medical condition, take medication, or are pregnant. Daylight is a food supplement and nothing here is a claim about what it does.
