How much exercise do you actually need to do to lose weight?

If your exercise goal is weight loss, rather than just achieving or maintaining a fitness level, you need to be burning more calories than you are eating. 

This may sound glaringly obvious, but it’s important because it means you have to monitor your calorie intake for the most effective weight loss exercise program.

Physical activity is associated with lower body weight (1) as well as with better bodily health and mental health (2, 3), so exercise helps you out all round.

But how much exercise do you ACTUALLY need to do to lose weight? 

The answers to this question were varied, so I tried to get to the bottom of it.

It partly depends on how much you weigh, what exercise you are doing, how vigorously you’re doing it, how often and for how long..

Walking

Walking has certainly been shown to work for weight loss (4, 5).

One recent study found people who walk briskly are more likely to have a lower weight than people doing other activities (6). Another study showed that without any dietary restriction, and building up to 60 minutes walking a day for 6 months lead to an average loss of 10% of body weight (7).

You need to find out how far you already walk every day to create a baseline, so you know how much extra distance you are covering with a new exercise regime. Pedometers are inexpensive and very effective at counting how many steps you take in a day. I don’t much like wearing things on my wrists though, so I prefer to keep a note of how long I walk for each day of the week.

If you currently walk 2 miles a day and maintain your weight it follows that you will need to walk more than 2 miles a day to start losing weight.

There are roughly 2100 steps in the average person’s mile, so if you use a pedometer you can work it out that way. At an average walking pace a mile takes about 15 minutes to walk. 

For every mile you walk you would burn somewhere around 83.5 calories (67.5 calories per mile for a 125 pound person, 83.5 calories/ mile for a 155 pound person and 100 calories per mile for a 185 pound person according to a HarvardMedical School exercise list). So if you walked an extra 3 miles every day that would be an extra 250 calories burned; over a week you would burn 1750 calories and over a month that would be 7000 calories.

The generally accepted guideline figure is 1 pound of body weight (mostly fat weight) equates to 3500 calories of either food or exercise. So over a month walking an extra 3 miles a day would lead to 2 pounds of weight loss. Over a year that would be 24 pounds! Obviously if you also adjust your diet the results would be much better.

3 miles is 6,300 steps which is 45 minutes of walking. By changing your habits for many people it’s quite possible to walk an extra 45 minutes a day- for example always take the stairs rather than the elevator, park at the end of the car park and walk, get out at lunchtime to eat lunch outside, or go out to buy lunch, walk while you’re on the phone etc.

High Intensity Interval Training (HIIT)

HIIT is a form of exercise where you alternate between all out activity and low level exercise. Generally HIIT sessions are between 15 and 25 minutes long.

HIIT has been shown to work well for fat loss for many people (8, 9, 10, 11, 12) as well as improving fitness and health markers (13).

HIIT may also be more effective than continuous moderate exercise as a treatment for metabolic syndrome (14).

HIIT is popular as it delivers on weight loss and fitness goals in a short period of time. If you’re short of time for exercise this might be the one for you.

It is hard to find any studies about how much HIIT you should do per week, but the general consensus seems to be 2-3 session per week maximum, allowing at least 24 hours body repair and recovery time in between. 

Session length around 15 to 30 minutes is usual. There are few studies to support these generally held views as yet however.

Two recent studies suggests HIIT burns around 13-15 calories per minute (15, 16). Taking 14 calories per minute as the average this would mean 350 calories from a 25 minute HIIT session. With 3 sessions a week that is 1050 calories; 4200 calories per month or just over a pound in weight loss.

Many people recommend combining HIIT sessions with resistance training to increase lean body mass.

Resistance Training (RT)

Resistance training involves exercising your muscles against resistance from your own body weight, dumbbells, resistance bands, weight bars or some exercise equipment.

Resistance training has been shown to help with weight loss and body fat reduction (17, 18, 19) and to increase strength (20). It may help increase bone mineral density, and help reduce lower back pain and discomfort associated with arthritis and fibromyalgia (21).

One study found a combination of aerobic and resistance training worked better to reduce body fat (22).

Unlike running or walking which uses the same action and muscles again and again, with resistance training the calorie expenditure is different depending on the workout you are doing. Where a heart rate monitor can be used to measure calories during aerobic exercise the relationship between heart rate and calories expended is not the same for resistance training.

Some exercises (eg. a barbell snatch) use large groups of muscles, while others might involve one isolated muscle only (eg. a bicep curl). 

The only easy conclusions are obvious one, like if you do a vigorous full body resistance workout it will burn more calories than a moderate workout on isolated muscles. You could add up the individual calories burned for each exercise if you were really keen. Some online resistance training resources give you the estimated calorie expenditure for the workouts.

The Harvard Medical School exercise list suggests a 30 minute resistance training session could use around 90 calories for a person weighing 125 pounds, 112 calories for a person weighing 155 pounds and 133 calories for a person weighing 185 pounds.

A recent study suggests that resistance training sessions fall into the category of vigorous exercise and so burn far more calories (23), with some strength based exercises burning more calories than previously estimated. For example it was suggested that pull-ups burn 9.95 calories, lunges 9.33 calories, push-ups 8.56 calories and curl-ups/ crunches 4.09 calories per minute.

Resistance training can boost your metabolism (24). One study found 14 hours after an intense 45 minute workout post calorie burn was still higher than before the workout. 

Other studies were less conclusive.

Muscle mass increases energy expenditure, so developing muscle mass through resistance training can increase the calories you burn daily, but there have been some over-exaggerated claims about the amount of calories burnt this way.

A 2003 comprehensive review of relevant studies by Donnelly et al * found resistance training over the test period (from 8 – 52 weeks) produced an increase of 2.2 to 4.5lb of muscle mass. 4.5lb of muscle mass would increase the resting metabolic rate (RMR) by around 50 calories per day. Although it’s not a massive amount, over time the effect would be significant. 

The same review also concluded that perhaps one of the most valuable benefits of resistance training during a calorie reduced diet is that it helps prevent the loss of fat-free mass. 

The effect of increased RMR after resistance training may be more in men than women however (25).

In conclusion, including at least 2 resistance training sessions of 25-30 minutes to your weekly exercise program., and increasing this to 3-4 after 3 months seems to be the general consensus. 

Using the conservative estimate of 112 calories burned in 30 minutes for a 155 pound person, 3 half hour sessions a week would mean 336 calories over the week. If you add the extra calorie burning as a result of extra muscle mass of around 50 calories per day (once you have built that muscle mass), this is 686 calories per week, or 2744 calories per month. 

Combining this with aerobic exercise of some type is recommended for fitness and weight loss. Many trainers also recommend combining resistance training with HIIT.

Doing resistance training along with HIIT or an endurance cardio exercise (such as walking, cycling or swimming) could really boost your weight loss.

Running

One 2012 study found that runners were leaner and lighter than people who did an equivalent amount of another exercise type (26). 

Weight loss has found to be greater for running than for walking (27). It has been suggested the break point for the difference between walking and running is between 4 and 5 miles per hour.

A Danish study found new runner who ran a minimum of 5km/3.1 miles per week but didn’t change their diet lost on average 8.4 pounds over 12 months. New runners who ran a minimum of 5km/3.1 miles per week and did change their diet lost an average 12.4 pounds (28) in a year.

The amount of calories burned by running depends on how fast you run, and also on your body weight. Running at 5 mph (12 min/mile) for 30 minutes would burn 240 calories for a 125 pound person, 298 calories for a 155 pound person and 355 calories for a 185 pound person. Running at 5.2 mph (11.5 min/mile) for 30 minutes would burn 270 calories for a 125 pound person, 335 calories for a 155 pound person and 400 calories for a 185 pound person (29).

When starting running you need to build up slowly to running longer distances and running more often, so you would not start running for 60 minutes every day for example. 

Running 3 times a week for 30 minutes as a 155 pound person at 12 mins/mile you could burn just under 900 calories per week, which would be 3576 calories per month, so a pound of weight lost. 

Increasing your running to 45 minutes at 12 min/ mile 3 times a week for a 155 pound person would be 1341 calories per week which is 5364 calories in a month which is around 1.5 pounds of weight.

When you exercise more there is a compensation effect, which means there is a tendency to eat more after exercising. So you do need to pay attention to your diet if you are exercising specifically for weight loss.

Swimming

Quite a number of early studies had results that suggested that swimming did not lead to fat or weight loss compared to other forms of aerobic exercise (30, 31, 32). Calorie burning appears to be as high as for other forms of exercise so the earlier negative results were puzzling. 

Various theories were put forward and investigated. At the end of the day it appears the most likely explanation for the lack of weight loss for swimmers in the early studies might simply be that cold water increases appetite. So after swimming, the body’s natural response to the cold water is to load up with extra calories, and in fact one study showed after cold water swimming energy intake as food we increased by up to 44% (33). 

A study in 2006 investigating this found swimming was as effective as land-based exercise for weight loss (34).

A report by Swim England (access the full report through this page) found swimmers live longer, swimming is especially valuable for people with joint or muscle issues, helps reduce stress and anxiety, and improves overall health and fitness for people in all age groups.

Swimming is a great full body exercise and doesn’t put pressure on joints as many other forms of exercise do. You can certainly use it to burn calories and lose weight if you do it regularly, but you need to be very careful about how much you eat.

TheHarvard Medical School exercise list suggests doing vigorous breaststroke a 125 pound person could burn 300 calories in 30 minutes, 155 pound person could burn 372 calories and a 185 pound person could burn 444 calories in 30 minutes. 

Swimming for 45 minutes 3 times a week would mean 1670 calories in a week for a 155 pound person, which is 6680 calories in a month, or over 1.75 pounds in weight. 

Cycling

Commuting to work by bicycle leads to around 1 stone in weight loss in the first year according to a recent study (35), and commuting to work by bicycle is linked to lower body mass index and lower body fat levels (36, 37).

Cycling to work can halve the risk of cancer and heart disease according to one five year study in the UK (38). 

Over 6 months with no dietary restriction, and building up to 60 minutes exercise a day one study found cycling lead to an average 12% drop in body weight (39).

Just about all the research I found around outdoor cycling for health and weight loss is based around commuting to work. In fact one Australian study found 60% of Portland cyclists rode for more than 150 hours a week, and the majority was for utilitarian purposes such as getting to work and back, rather than specifically for exercise or leisure (40).

However there were some studies around indoor cycling.

A 2016 study found using an under the desk mini exercise bike during the working day for around 50 minutes a day lead to improvements in general health and also to weight loss for a group of office workers (41).

A study found outdoor cyclists exerted more energy and had higher heart rates than when the same cyclists used indoor exercise bikes, and the difference in power exerted was as much as 25%. The study author suggested cycling indoors may distort your perception of how hard you are working compared to outdoor cycling (42). 

Indoor cycling, or spinning, is still a very valid form of exercise and a great way to lose weight.

Using a high intensity sprint training routine for just 10 minutes on an exercise bike could have the same health benefits as 50 minutes of moderate endurance training according to a study in the online journal PLOS ONE (43).

According to the Harvard exercise list cycling at 12 -13.9 miles per hour burns 240 calories in 30 minutes for a 125 pound person, 298 calories in 30 minutes for a 155 pound person and 355 calories for a 185 pound person.

Cycling slightly faster at 14 -15.9 mph burns 300 calories in 30 minutes for a 125 pound person, 371 calories for a 155 pound person and 444 calories for a 185 pound person. 

Pedalling even faster at 16-19mph burns 360 calories in 30 minutes for a 125 pound person, 446 calories for a 155 pound person and 533 calories for a 185 pound person.

At an average speed of 14-15.9 mph, cycling for 60 minutes 3 times a week 2226 calories would be burned for a 155 pound person. That's 8904 calories in a month, or over 2.5 pounds in weight. 

Using an exercise bike with moderate intensity burns 210 calories in 30 minutes for a 125 pound person, 260 calories for a 155 pound person and 311 calories for a 185 pound person. 

Using an exercise bike at vigorous intensity burns 315 calories in 30 minutes for a 125 pound person, 391 calories for a 155 pound person and 466 calories for a 815 pound person.

For a 155 pound person using an exercise bicycle at moderate intensity for 60 minutes 3 times a week, 1560 calories would be burnt in a week, 6240 calories in a month, around 1.75 pounds in weight.

Summary

All forms of exercise can help with weight loss if done consistently. Keeping an eye on your diet to ensure you don’t eat more when you exercise is important too.

A combination of an endurance cardio exercise like walking, running, swimming or cycling done 5-7 days a week for 30-60 minutes with 2-3 HIIT or resistance training sessions of 20-30 minutes looks a good safe bet for healthy noticeable weight loss.

You have to find an exercise you can fit into your daily routine, because setting a habit is the key to long term change. If the gym is not on the way to or from work, it’s going to make it harder to get to the gym on a regular basis for example. If the swimming pool is a 1 hour bus ride it’s going to be hard to make that work around the rest of life.

At the end of the day, the best form of exercise is one you really like or enjoy so you can do it consistently, because that really is the key. There are so many different forms of exercise to choose from. If dancing is your thing – dance; if rock-climbing is your thing- get climbing. There’s no point choosing HIIT and swimming if you hate high intensity training and cold water because a) it’ll be hard to keep up in the long term and b) really what’s the point in making yourself miserable when you could be doing some you enjoy more? 

*REFERENCES NOT AVAILABLE ONLINE:

Donnelly, J.E., Jakicic, J.M., Pronk, N., Smith, B.K., Kirk, E.P., Jacobsen, D.J., Washburn, R. “Is Resistance Training Effective for Weight Management?” Evidence-Based Preventive Medicine. 2003; 1(1): 21-29.