Hot Tub Weight Loss: Does Soaking Help You Lose Weight?

Hot tub weight loss is mostly a myth if you mean losing body fat by soaking. Sitting in hot water can raise body temperature, heart rate, and energy use for a short time, but the effect is small compared with exercise and has not been shown to produce meaningful weight loss on its own.

The better way to think about a hot tub is as a relaxation or recovery tool that may fit around a healthy routine. It should not replace regular physical activity, nutrition changes, sleep, or medical care for weight management.

Can a Hot Tub Help You Lose Weight?

A hot tub is not an effective standalone weight-loss method. Weight loss requires a sustained energy deficit over time. The CDC explains that physical activity increases the calories your body uses, while reducing calories from food and drinks can help create the calorie deficit needed for weight loss.

Current passive-heating research does show that hot water changes some short-term physiological responses. That does not mean sitting in a hot tub is equivalent to walking, cycling, strength training, or another form of exercise.

The CDC’s current guidance on physical activity and weight management recommends at least 150 minutes of moderate-intensity aerobic activity per week for general health, plus muscle-strengthening activity on at least 2 days.

Do Hot Tubs Burn Calories?

Yes, your body continues to use energy while you sit in a hot tub, and heating the body can increase energy expenditure somewhat. The important question is how much extra energy is used compared with simply resting.

A frequently cited 2017 experiment involved only 14 men. Participants either cycled for 60 minutes or sat waist-deep in 104°F (40°C) water for 60 minutes. The researchers reported that passive heating increased energy expenditure by about 61 calories per hour above resting expenditure. Exercise increased energy use far more.

You can read the original passive-heating study. It is useful research, but it was a small laboratory experiment and not a trial showing that hot tubs cause weight loss.

This is why a hot tub calorie calculator is misleading. Calorie expenditure varies by body size, resting metabolism, water temperature, immersion depth, session length, and other factors. A single formula cannot accurately tell a hot tub owner how many calories a soak burned.

Where Does the “140 Calories in an Hour” Claim Come From?

The popular claim that an hour in hot water burns around 140 calories comes from interpreting the total energy expenditure in that small passive-heating experiment. The more useful number is the increase above normal resting energy use, which was about 61 calories per hour in that study.

That does not mean every person will burn an extra 61 calories in every 60-minute hot tub session. It also does not mean a long soak is a smart way to chase calorie burn. The study conditions were controlled, and the sample was very small.

Does Sweating in a Hot Tub Burn Fat?

No. Sweating is primarily your body’s cooling system, not a sign that body fat is melting away. A hot soak may make the scale read slightly lower immediately afterward because you lost fluid through sweat. That weight generally returns when you rehydrate.

Cleveland Clinic explains that sweating itself does not determine calorie burn and that short-term weight loss from sauna-type heat is mainly water loss rather than fat loss. See its explanation of sweating, calories, and water weight.

Does a Hot Tub Boost Your Metabolism?

Hot water can temporarily increase cardiovascular and thermoregulatory demands. In plain language, your body has to work to manage the extra heat. That can raise energy expenditure for a limited period.

What is not established is that this temporary response creates a meaningful long-term increase in metabolism or produces sustained weight loss. A 2025 systematic review and meta-analysis of 20 randomized trials found no significant pooled effects for most measured cardiometabolic outcomes, including fasting glucose, HbA1c, cholesterol, triglycerides, resting heart rate, and several vascular measures.

The review did find possible blood-pressure effects in some subgroups, but the authors advised caution because the studies were varied and had limitations. You can review the 2025 passive-heating systematic review.

Does Repeated Heat Exposure Cause Weight Loss?

There is not good evidence that repeated passive heating causes meaningful weight loss. One study in 11 overweight adults used 10 consecutive days of passive heat exposure. Researchers reported some changes in glucose and metabolic markers, but body weight did not significantly change.

That study used long controlled heat exposures, not normal backyard hot tub sessions. It is another reason to separate possible metabolic research from claims that a hot tub is a weight-loss treatment. The full study is available through PubMed Central.

Can a Hot Tub Still Support a Weight-Loss Routine?

A hot tub may still have a practical place in a healthy routine, just not as the part that directly drives fat loss.

• Relaxation: A soak can be a pleasant way to unwind without adding calories from food or alcohol.
• Post-workout comfort: Warm water may feel soothing after activity, although recovery benefits should not be exaggerated.
• Routine building: Some people may use a soak as a consistent end-of-day cue after exercise, stretching, or another healthy habit.
• Low-impact movement: If you want actual movement in the water, use a dedicated exercise routine rather than counting passive soaking as exercise.

For movement ideas, see our hot tub workout routines. Keep in mind that exercising in very hot water increases heat stress, so comfort and safety matter more than trying to maximize calorie burn.

What About Using a Hot Tub After Exercise?

A hot soak after exercise may feel good, but that does not mean it increases fat loss. Recovery, hydration, sleep, and a sustainable exercise routine matter more for long-term progress.

Our guide to a hot bath after a workout looks specifically at heat, muscle recovery, and muscle growth without treating heat as a shortcut for fitness.

What Actually Matters Most for Weight Loss?

The CDC emphasizes the combination of eating patterns and physical activity for weight management. Most weight loss comes from reducing calorie intake, while regular physical activity is especially important for health and maintaining weight loss.

• Build an eating pattern you can sustain.
• Accumulate regular moderate or vigorous physical activity.
• Include muscle-strengthening activity.
• Get enough sleep and manage stress in practical ways.
• Use the hot tub for enjoyment, relaxation, or comfort rather than as a calorie-burning target.

Do Not Extend Hot Tub Time Just to Burn More Calories

Trying to stay in hotter water for longer just to increase calorie expenditure is not a useful weight-loss strategy. Heat exposure can lead to dizziness, nausea, weakness, dehydration, and overheating.

The CDC says hot tub water should not be higher than 104°F (40°C) and advises against drinking alcohol before or during hot tub use. Its guidance focuses on safe heat exposure and sanitation, not using longer sessions to burn calories.

For a deeper explanation of heat stress, see our guide to hot tubs and body temperature. You can also review the CDC hot tub safety recommendations.

Frequently Asked Questions

Can sitting in a hot tub make you lose weight?

Not in a meaningful or reliable way. A soak may slightly increase energy expenditure and may cause temporary water loss from sweating, but neither effect is the same as sustained body-fat loss.

How many calories do you burn in a hot tub for 30 minutes?

There is no reliable universal number. In one small study, 60 minutes of 104°F waist-deep immersion increased energy expenditure by about 61 calories above resting levels, but that result should not be turned into a personal calorie calculator.

Does sweating in a hot tub burn belly fat?

No. Sweating mainly causes fluid loss. Any quick drop on the scale after a hot soak is usually temporary water weight and returns after rehydration.

Do hot tubs boost metabolism enough to lose weight?

Heat can temporarily increase energy expenditure, but current research does not show that this creates meaningful long-term weight loss. Physical activity and calorie intake remain much more important.

Is a hot tub useful after a workout when trying to lose weight?

It can be useful for relaxation or comfort after exercise, but it does not add a proven fat-loss effect. Rehydrate, avoid excessive heat exposure, and treat the soak as recovery time rather than another calorie-burning workout.

The Bottom Line

Hot tub weight loss should not be sold as a shortcut. Passive heating can raise energy expenditure a little and may affect some short-term physiological markers, but the evidence does not show that ordinary soaking produces meaningful fat loss.

Use your hot tub because you enjoy it, because it helps you relax, or because warm water feels good after activity. For actual weight management, put your effort into sustainable eating habits, regular physical activity, strength training, sleep, and other behaviors that have much stronger evidence behind them.