Strength, health and age
What the WHO and the ACSM recommend, why strength is critical past 40, and how to combine cardio and weights without losing anything.
Strength training stopped being a gym thing and became a public-health recommendation. The reason is simple: muscle mass and strength predict function, independence and quality of life in the second half of life.
The official recommendation
Muscle-strengthening work at least two days a week
The WHO recommends that adults do muscle-strengthening activities of moderate or greater intensity, covering all major muscle groups, on two or more days a week, in addition to weekly aerobic activity. The 2026 ACSM position stand — built on 137 systematic reviews and more than 30,000 participants — reinforces that the big jump is going from not training to training regularly.
- Strength
- ~80% 1RM, 2–3 sets per exercise
- Hypertrophy
- ~10 weekly sets per muscle group
- Power
- 30–70% 1RM with a fast concentric
Past 40: sarcopenia
With age you lose mass and, above all, strength and power, which fall faster than size does. That loss is linked to falls, frailty and loss of independence. Strength training is the intervention with the best evidence for reversing part of the process. Past that age creatine also changes role — from a gym product to a tool for physical function — and it is one of the few supplements that contribute here (why).
Strength training improves physical function in older people, even with sarcopenia
Systematic reviews in older adults with sarcopenia show consistent improvements in grip strength, gait speed, sit-to-stand tests and timed up and go. The effects on muscle mass are more modest than the effects on function, which is what determines independence.
Check first if you have a condition
This guide is evidence-based education, not an individual prescription. If you have a cardiovascular, metabolic or musculoskeletal condition, or you are pregnant, the plan should be validated by a healthcare professional.
Cardio and weights together
The “interference effect” is overstated
Interference shows up mostly at high endurance training volumes (roughly from 4–5 weekly sessions) or when aerobic work clearly outweighs strength work. Within the same session, the meta-analysis by Eddens and colleagues observed an advantage for strength when the strength work comes first.
- Separate hard cardio and leg work by at least 6 hours, or put them on different days.
- If they go together, weights first.
- Low-intensity cardio (walking) does not interfere and improves recovery.
Other populations
| Population | What changes |
|---|---|
| Women | The same principles and ranges. Volume tolerance tends to be better and recovery between sets somewhat faster. |
| Adolescents | Supervised strength training is safe; prioritise technique and slow progression. |
| Over 65s | Start with machines or stable variants, add power work (fast concentric) and balance training. |
| Returning from injury | Load progression guided by symptoms and by the judgement of the professional treating you. |
Takeaways
- Two strength days a week is the minimum with the best benefit-to-effort ratio.
- Past 40 the priority is strength and power, not just size.
- Cardio adds; it only interferes at high volumes.
- With a diagnosed condition, a healthcare professional signs off the plan.
Sources for this chapter
- [1]Organización Mundial de la Salud (2020). WHO guidelines on physical activity and sedentary behaviour. OMS. official guideline
- [2]American College of Sports Medicine (2026). Position Stand: Resistance Training for Healthy Adults. ACSM. position stand
- [3]Revisión sistemática y meta-análisis en adultos mayores con sarcopenia (2025). Optimal resistance training prescriptions to improve muscle strength, physical function, and muscle mass in older adults diagnosed with sarcopenia. Aging Clinical and Experimental Research. meta-analysis
- [4]Bosquet L, Berryman N, Dupuy O, et al. (2022). Use It or Lose It? A Meta-Analysis on the Effects of Resistance Training Cessation (Detraining) on Muscle Size in Older Adults. International Journal of Environmental Research and Public Health. meta-analysis
- [5]Eddens L, van Someren K, Howatson G (2018). The Role of Intra-Session Exercise Sequence in the Interference Effect: A Systematic Review with Meta-Analysis. Sports Medicine. meta-analysis