From roughly your late thirties you lose muscle mass and strength every year unless you do something about it. Resistance training is the something. The evidence that it works is unusually strong.
What the evidence shows
Randomised trials in middle-aged and older adults consistently show that resistance training increases muscle mass, strength and functional capacity, at every age tested, including in people in their eighties and nineties. It improves bone density, insulin sensitivity and balance, and in older adults it reduces falls, which are one of the main routes by which independence is lost.
This is one of the few areas in lifestyle medicine where the trials are numerous, the effects are large and easily measured, and the direction is never in doubt.
How much difference it makes
Large. Not in the sense of adding decades, but in the sense of changing what your later years look like. The difference between an eighty year old who can stand up from a chair unaided and one who cannot is largely a difference in leg strength, and leg strength is trainable.
Strength gains begin within weeks. Visible muscle takes months. Most of the health benefit arrives with the strength, not the appearance.
What to do
Two sessions a week is enough for most of the benefit. You do not need a gym, though it helps.
- Pick around six movements covering legs, a push, a pull and something for the trunk.
- Work in a range where the last two or three repetitions are genuinely hard.
- Add a little weight, or a repetition, when a set stops feeling difficult.
- Bodyweight counts at the start. Squats to a chair, press-ups against a wall, and carrying shopping are all legitimate beginnings.
Consistency beats intensity. Two moderate sessions every week for a year beats a punishing programme abandoned in March.
Cautions
If you have uncontrolled high blood pressure, a recent cardiac event, a hernia, or significant joint disease, get individual advice before starting. The general recommendation is safe for most people, and you may not be most people.
Soreness for a day or two after a new movement is normal. Sharp pain during a movement is not, and you should stop.
When to see a doctor
Chest pain, unusual breathlessness or dizziness during exercise needs assessing before you continue. Do not train through those.