How much rest do my muscles need between training sessions as I get older?

As you get older, muscle tissue responds less powerfully to training stimuli. This phenomenon is called anabolic resistance: the muscle essentially needs a higher threshold before it will grow or become stronger. At the same time, recovery after inactivity, a hospital stay, or an injury is demonstrably slower in older people than in younger ones. This does not mean that training becomes pointless, but it does mean that you need to approach it more intelligently.

Large meta-analyses show that for muscle growth two training sessions per week produce the best results, while for strength development three sessions per week are most effective. Both conclusions are based on large numbers of studies (119 and 178, respectively), involving multiple sets and heavier weights. An intervening rest of 48 to 72 hours per muscle group is therefore implicitly built in: if you train two or three times per week, each muscle group has at least one to two days of recovery per cycle. The available studies provide no indication that older adults necessarily need more rest days than this basic schedule, but the importance of not getting too little rest is underscored by the difficulty older people have recovering from muscle loss.

A study in 75-year-olds shows that training heavily twice a week (at 70% of maximum weight) produces measurable gains in muscle mass and strength after just six weeks. Those who cannot tolerate heavy loading due to joint pain or another condition may consider blood-flow restriction training with light weights: after twelve weeks this yields comparable muscle growth, although strength development in the first few weeks is somewhat slower.

Nutrition makes a concrete difference. Older adults aged 65 and over who increase their protein intake to 1.2 to 1.6 grams per kilogram of body weight per day while also doing strength training build significantly more muscle mass than people who only train. The effect is modest but consistent across 62 studies. Creatine supplementation can additionally enhance the training effect somewhat, probably because it promotes recovery after exercise. Creatine without training, however, does little for older adults.

Finally, there is early research into the combination of nicotinamide (vitamin B3) and pyridoxine (vitamin B6) as a support for muscle stem cells. In animal models this accelerated muscle recovery, and in an observational study of 186 older people there was an association with greater muscle mass and a higher walking speed. This is an interesting signal, but it has not yet been investigated in large-scale human trials, so no practical advice can be based on it at this stage.