Swimming is one of the UK's most popular exercise activities, with over 5 million adults swimming at least once a week. It offers a unique combination of cardiovascular fitness, muscle strength, and flexibility training with minimal impact on joints - making it suitable for all ages and fitness levels. Whether you swim at your local leisure centre, an outdoor lido, or an open water venue, understanding the calorie burn can help you plan your fitness goals effectively.
MET (Metabolic Equivalent of Task) values measure exercise intensity relative to rest. A MET of 1.0 is your resting metabolic rate. The calorie formula is: Calories = MET x body weight (kg) x duration (hours).
| Stroke | Slow MET | Moderate MET | Vigorous MET | Cal/hr (75kg moderate) |
|---|---|---|---|---|
| Freestyle (Front Crawl) | 5.8 | 8.3 | 9.8 | 623 kcal |
| Breaststroke | 5.3 | 9.3 | 10.3 | 698 kcal |
| Backstroke | 4.8 | 8.5 | 9.5 | 638 kcal |
| Butterfly | - | 11.0 | 11.0 | 825 kcal |
| Leisure / Recreational | 3.5 | 4.5 | - | 338 kcal |
| Water Polo | - | 10.0 | - | 750 kcal |
| Activity | Calories (kcal/hr) | Impact Level | Muscles Used |
|---|---|---|---|
| Freestyle swimming (moderate) | 623 | Very Low | Full body |
| Running (6mph) | 650 | High | Lower body dominant |
| Cycling (moderate, 12-14mph) | 563 | Low | Lower body dominant |
| Gym (weights, moderate) | 375 | Low-Medium | Targeted |
| HIIT workout | 700-900 | High | Full body |
| Walking (brisk, 4mph) | 300 | Low | Lower body |
Swimming provides exceptional health benefits beyond calorie burning. The NHS and Sport England recognise swimming as one of the most complete forms of exercise available:
The NHS recommends adults aged 19-64 complete at least 150 minutes of moderate-intensity aerobic activity per week, or 75 minutes of vigorous-intensity activity. Moderate swimming (comfortable pace, able to talk) counts as moderate-intensity. Vigorous swimming (out of breath, unable to sustain a conversation) counts as vigorous-intensity activity.
For weight loss, 150 minutes of moderate swimming burns approximately 1,250-1,750 calories per week (for a 75kg person), equivalent to losing 0.35-0.5kg of body fat per week combined with dietary changes.
Structure your swimming sessions for maximum fat burn:
| Pool Type | Per Session | Monthly Membership | Notes |
|---|---|---|---|
| Council leisure centre | £3.50-£6.00 | £25-£40 | Often has concession rates |
| Private health club | £6.00-£12.00 | £40-£90 | Better facilities |
| London council pool | £5.00-£8.50 | £35-£55 | Higher London costs |
| Outdoor lido | £4.00-£8.00 | Season ticket | Seasonal (May-Sept) |
| Open water swimming | Free-£5.00 | Club fees vary | Wild swimming locations |
A 75kg person swimming at moderate pace burns approximately 350-450 calories in 30 minutes, depending on the stroke. Breaststroke at moderate pace burns around 350 calories, freestyle at moderate pace around 415 calories, and butterfly (the most intense stroke) can burn up to 413 calories in 30 minutes. Vigorous swimming of any stroke burns significantly more - up to 550+ calories per 30-minute session.
Butterfly is the most calorie-intensive swimming stroke, with a MET value of approximately 11.0. This means a 75kg swimmer burns around 825 calories per hour doing butterfly - though few recreational swimmers can maintain it for a full hour as it is extremely technically demanding and exhausting. Vigorous breaststroke comes second at around 773 calories per hour, followed by vigorous freestyle at around 735 calories per hour for a 75kg swimmer.
Yes, swimming is excellent for weight loss. It burns significant calories while being low-impact on joints, making it suitable for people who cannot run or do high-impact exercise. For weight loss, aim for 150+ minutes of moderate swimming per week (as per NHS guidelines) combined with a calorie-controlled diet. A 75kg person swimming moderately for 45 minutes 4 times per week could burn an additional 2,500-3,000 calories per week, equivalent to losing approximately 0.7-0.8kg of body fat weekly if combined with dietary changes.
Vigorous freestyle swimming burns approximately 620-750 calories per hour for a 75kg person - comparable to running at 6mph (about 650 calories/hour). Running burns slightly more calories at equivalent intensities due to the full weight-bearing nature of the exercise. However, swimming is significantly lower impact, meaning you can exercise longer without fatigue or injury risk. Swimming also engages the upper body much more than running, providing better whole-body conditioning.
Lane swimming at a UK public leisure centre typically costs £3.50-£6.00 per session in 2026. Monthly memberships offering unlimited swimming average £25-£40 at council leisure centres. Many councils offer discounted rates (typically 30-50% off) for Over 60s, students, and benefit recipients. London pools are generally 30-50% more expensive than equivalent facilities in northern England or Wales. Many areas have free swimming schemes for under-16s and over-60s.
Before swimming, eat a light meal or snack 1-2 hours before your session. A banana, porridge, or a small wholemeal sandwich works well. Avoid heavy or fatty meals immediately before swimming as this can cause discomfort and stitch. After swimming, aim to eat within 30-60 minutes - focus on protein to aid muscle recovery (chicken, eggs, Greek yogurt, tuna) combined with some carbohydrates (wholegrain bread, brown rice) to replenish glycogen stores depleted during exercise.
Yes, research consistently shows swimming benefits mental health significantly. Swimming triggers endorphin release, reducing stress and anxiety. The rhythmic, repetitive nature of lap swimming has been compared to mindfulness meditation - the focus required on breathing and technique creates a meditative state that quiets mental chatter. Regular swimmers report improved mood, better sleep quality, and reduced symptoms of depression and anxiety. Cold water swimming in UK rivers, lakes and lidos has gained particular attention for its mood-boosting and immune-system benefits.