Swimming benefits: what the evidence shows, and how to build a regular swim

What the research shows

• A longer life. The 2024 review by Oja and colleagues pooled 136 papers from 76 studies. For swimming, the pooled hazard ratio for death from any cause was 0.76, a 24% lower risk, along with improvements in body composition and blood lipids.
• A healthier heart. In the 2017 British cohort study, also led by Oja, swimmers had a lower risk of death from cardiovascular disease (hazard ratio 0.59) than non-swimmers, after adjustment for other factors.
• Lower blood pressure. Igarashi and Nogami pooled 14 randomised trials with 452 participants. Regular aquatic exercise lowered systolic pressure by 8.4 mmHg and diastolic by 3.3 mmHg. The authors noted that forms other than swimming, such as water aerobics, also lowered blood pressure.

Cohort studies cannot rule out that healthier people choose to swim, which is why researchers adjust for age, smoking, other activity and illness. The direction of the findings is the same across studies, and it matches what the trials show on blood pressure.

How hard swimming really is

Effort varies far more in water than on land, because technique decides how much of your energy moves you forward. The 2024 Compendium of Physical Activities gives these values:

• Leisurely swimming, not laps: 6.0 METs.
• Backstroke, recreational: 4.8 METs.
• Breaststroke, recreational: 5.3 METs.
• Front crawl, slow: 5.8 METs.
• Front crawl, medium speed: 8.0 METs.
• Freestyle laps, fast and vigorous: 9.8 METs.

The World Health Organization counts 3 to under 6 METs as moderate and 6 or more as vigorous. A gentle breaststroke counts towards the 150 minutes of moderate activity; a steady front crawl usually counts as vigorous, where 75 minutes a week is enough. The calculator below estimates your heart rate ranges from your age and resting pulse, the method explained in our guide to zone 2 training. In the pool a watch is hard to read, so the talk test at the wall is a useful check: at a moderate effort, the NHS says, you can still talk but not sing.

Your first month in the pool

If you are not confident in deep water, start with adult lessons. Otherwise:

1. Week 1: swim one length, rest 30 to 60 seconds at the wall, repeat for 15 to 20 minutes. Mix strokes if one tires you.
2. Week 2: swim two lengths before each rest. Add a few lengths with a kickboard to work the legs.
3. Week 3: aim for 25 minutes of swimming, resting only when your breathing needs it.
4. Week 4: try sets, for example four times 100 metres with 30 seconds' rest, to build continuous swimming.

Count lengths or minutes, not speed. Goggles make front crawl easier to learn, because you can see the bottom and keep your head low.

How often to swim

The World Health Organization recommends 150 to 300 minutes of moderate activity a week, or 75 to 150 minutes of vigorous activity, and the NHS suggests spreading it over four to five days or more. Three swims of 25 to 30 minutes at a steady crawl, or four sessions of 40 minutes of easy breaststroke, both fit. See how much exercise per week for the full picture.

Swimming does not appear in the NHS list of muscle-strengthening activities, so the week still needs two strength sessions. A short bodyweight circuit, as in the hotel room workout, fills that gap. On dry days, cycling is another low-impact way to add aerobic minutes.

Water safety and other precautions

The World Health Organization counts around 300,000 drowning deaths a year worldwide. Men drown at more than twice the rate of women, and the WHO links part of that gap to riskier behaviour such as swimming alone and drinking alcohol before swimming.

• Swim in a supervised pool or at a lifeguarded beach, especially in open water.
• Never drink alcohol before swimming.
• In open water, check currents and temperature, and swim with someone.
• Shower afterwards and dry your ears well if they tend to get irritated.

If you have a heart condition, high blood pressure that is not controlled, epilepsy, or you have been inactive for a long time, talk to your doctor before you start a swimming programme. Stop and get out of the water if you feel chest pain, unusual breathlessness or dizziness.

Make your swims part of a crew's week on Never Skip Club

Swimming covers your aerobic work; strength still needs its two days, and regularity matters more than any single long swim. Create your free account, build a guided strength session in a minute for the days out of the pool, and start a crew of friends with a weekly rhythm: the ranking rewards turning up as planned, not doing more. If you want an expert to plan your sessions, find a coach from our network, or sign in if you are already a member.