Does stretching actually help, or is it a waste of effort?
Stretching demonstrably improves flexibility, and 10 minutes per week is already enough for the maximum effect. For preventing injuries, however, it does not work; eccentric strength training is far more effective for that purpose.
If you want to become more flexible, stretching definitely works. A meta-analysis of 189 studies involving more than 6,600 adults shows that even a single stretching session produces a noticeable improvement in mobility1. If you keep that up weekly, you reach the maximum benefit with as little as 10 minutes per week. Doing more after that barely adds anything extra. If you are already fairly flexible, you have less to gain than someone who starts out stiff.
For sport, the type of stretching you choose does matter. Long static stretching of 60 seconds or more per muscle group immediately before a training session temporarily reduces strength and explosiveness by around 4 to 5 percent2,3. Short static stretching under 60 seconds has hardly any downside, especially if you follow it up with some active movement. Dynamic stretching, in which you swing your limbs loosely through their full range of motion, actually has a small positive effect on performance and is therefore the smartest warm-up choice4,2,3.
A persistent misconception is that stretching prevents injuries. That is not correct. Studies show no convincing evidence that static or PNF stretching (alternately contracting and relaxing a muscle) reduces overall injury risk2,5. If you want to prevent hamstring injuries, eccentric strength training, such as the Nordic hamstring exercise, works far better: studies show a reduction of 57 to 70 percent with that approach5.
For specific complaints, stretching can be useful. People with non-specific low back pain who stretched their hip muscles three times a week for six weeks showed measurably less pain, fewer limitations and better balance compared with a sham treatment6. For shoulder tendon problems, flexibility exercises appear to offer more benefit than for tendon problems at the knee or ankle, but the studies behind this are of low quality; a physiotherapist can help you further here7.
Finally, greater flexibility is not always better. In runners, a degree of muscle stiffness is actually associated with a more efficient running technique, because the muscles store more energy with each stride8. The value of stretching therefore stands or falls with your goal.
Based on one large meta-analysis of 189 randomised studies (more than 6,600 participants) for mobility, multiple systematic reviews for sports performance and injury prevention, one randomised study for low back pain, and one network meta-analysis for shoulder tendon conditions. The evidence for injury prevention through stretching is limited and largely observational.
Is sitting a lot harmful, even if I exercise enough?
If you meet the exercise guideline, that largely neutralises the risk of prolonged sitting. If you do not meet it, every additional hour of sitting counts. Prolonged TV viewing is a point of attention even for physically active people.
Does walking do enough to maintain your muscles?
Walking alone is not enough to maintain muscle as you age. Add strength training and ensure adequate protein intake for the best results.
Is it helpful to occasionally go for a long walk, or are short bursts of movement spread throughout the day better?
Short bursts of movement spread throughout the day appear to be at least as valuable as one long walk, and for people who otherwise do not exercise even a few minutes of vigorous movement per day is already meaningful. Combine both: move regularly in short, vigorous bursts and avoid prolonged sitting blocks of more than half an hour.
Is walking enough, or do I really need to do strength training too?
Walking is good, but strength training adds something walking cannot: preserving muscle mass, strengthening bones and keeping your metabolism in shape. Even half an hour of muscle-strengthening exercises per week makes a measurable difference.
How much exercise do I need to live longer?
The biggest health gain comes from just a little exercise. Going from nothing to 150 minutes per week gives a 31% lower risk of premature death; after that the benefit increases somewhat more, but levels off.
Does creatine also help ordinary people, not just athletes?
Creatine is not just for athletes. Combined with resistance training, it helps older adults gain muscle strength, and probably also improves memory.