Resistance Exercise Training (RET) is good for you.
Muscle mass begins a slow decline from about 30 years of age, accelerating into old age and resulting in sarcopenia for most older people. There is a fair amount of strength in reserve at the beginning of this process but ultimately there may not be enough to cope with daily life activities. Falls and fractures are bad news for the frail elderly.
Good news – old muscles respond to training in just the same way as young ones. For a review of the science regarding RET in older folk see <HERE>.
Strength (resistance) training is effective in elderly persons and can be undertaken without notable adverse effects.
Strength (resistance) training is subject to a dose-response relation. Higher intensities yield greater effects than low or medium intensities.
Strength (resistance) training in elderly persons aims to increase muscle mass (hypertrophy) on the one hand, and on the other hand, promote neuronal adaptation (intermuscular and intramuscular coordination).
If you have despaired at the mythology surrounding diet or cycling be ready to ignore an even greater torrent of nonsense regarding doing weights. High reps, low weights for stamina, low reps very high weights for strength, medium reps medium weights for bulk. It’s all frog shit.
The reality is that the results depend on the intensity and your genes. Light weights and many reps until exhausted will have the same result as heavy weights and few reps until exhausted. The key is the exhaustion. Near exhaustion is very nearly as effective and has a few advantages!
Recovery and avoiding over-training are the other side of the coin. The science to back up these last few paragraphs can be found in a review paper by Morton et al. Their key recommendations include choosing weights that lead to volitional fatigue, three times per week with a total of at least 10 reps per muscle group and not more than 15 sets per muscle group.
And that leaves plenty of scope. I favour beginning with compound exercises such as squats and lat pull-downs, heavy enough so that 10 to 12 is the limit, 2 or 3 sets, followed by 1 set each for whichever individual muscles best serve your vanity. Don’t waste too much time on the biceps it’s the lats and deltoids that make the upper body!