Ask HN:How many calories can non-athlete burn in one shot without been exhausted | Hacker News Reader

Ask HN:How many calories can non-athlete burn in one shot without been exhausted

Hi friends,

As a quite-inactive guy, I'm curious how many calories can you burn in one exercise session without getting hurt. By saying "getting hurt" I intend to include all minor injuries that jeopardize your next session or your work so that's why I put "exhausting too much" in the title.

I imagine for someone who is active and has good joints, he/she might be able to burn 400-500 calories every day BEFORE going to work. But is anything more than that, say, 800-1000 calories possible for you? I guess it's a completely different picture for athletes so this is targeted for laymen.

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Is your goal actually to burn calories or to lose weight? If it is to lose weight, focusing more on your eating habits is probably higher value than exercise. Exercise is good for feeling better and burning some calories, but it's probably easier to not eat 1000 extra calories than it is to consistently burn that many calories without giving up. Also for me exercise makes me feel good and want to reinforce my hard work by eating decently, so I think diet and exercise are both important. If you are only focusing on exercise, you might end up being hungrier because of the calories you are burning and end up eating more calories than you would have doing less exercise.

> Exercise is good for feeling better and burning some calories, but it's probably easier to not eat 1000 extra calories than it is to consistently burn that many calories without giving up

This isn't really true. When you exercise daily, your muscles will be able to store and burn more calories every day (like 10-20% more a day), it is the meaning of being active, not sedentary. The body have pathways that will only activate when you are active yourself.

Also, Lowering the amount of calories ingested lower the metabolism, especially if you are inactive, making it even. The best route is to do both: eat more nutrient dense food,less caloric and use the energy your body already have stocked.

You're not asking the right question. Caloric expenditure during exercise varies a lot based on body size and other factors. The risk of injury varies based on sport and technique: trail running has a much higher injury risk than using an elliptical machine.

If you're starting an exercise program then ignore calories. Start out doing short, low intensity workouts. Then gradually ramp up the intensity and length over several months. This will give your body time to adapt to the load and minimize injury risk.

>This will give your body time to adapt to the load and minimize injury risk.

This is great advice. For the longest time I would exercise like I was still a jock, injuring myself after a month or so and completely stopping because of it. I now realize my jock days are looong over and I need to exercise to keep my heart healthy and not try to be the hulk or something.

Even a 400 calorie workout would be pretty impressive for a non-athlete. In gross terms that’s a full hour long swimming session. You’d be hard pressed to do that without first training for it.

Conversely, not drinking 2 IPAs gets you to the same place.

If you are looking for calorie deficit your intake is much easier to change than your outputs.

The lowest risk to high burn ratio is probably swimming in a non-heated pool. Whether a person can burn that many calories doing that, depends on the lenght of the session, and their body and muscle mass. The heavier a person is, the more calories they burn just by breathing. Same with muscle.

Thanks to some people, a calorie as defined in the SI is 1/1000 a CAL as written in food packaging. So people keep saying calories when actually talking about kilocalories. So by breathing for a couple of minutes an adult burns about a 1000 calories (or 1 CAL or 1 kcal).

There is no completely safe activity. You can pull a muscle just by laying on a sofa, or get back pain from sitting incorrectly.

Exercise mitigates these risks and increases others. The sweet spot for adults, as per the WHO, is between 2.5 to 5 hours of aerobic exercise per week, and about 2 hpk of strength exercise. More than that and injuries outweigh benefits.

Can anyone lose a 1000 kcal per day extra by exercising? Probably. Can anyone spend two or three hours doing laps at the pool, daily, for the foreseeable future? Doubtful.

As long as you're otherwise healthy and use proper technique there is no reliable evidence that more than 5 hours per week of aerobic exercise increases risk of injuries more than benefits. In fact the WHO states that more than 5 hours per week provides "additional health benefits".

https://www.who.int/news-room/fact-sheets/detail/physical-ac...

The injury risk comes not from hours per se but from impact and intensity. For example, a 1 hour running intervals workout will generally carry a much higher injury risk than a 1 hour cycling tempo workout.

Find a gym with classes like Zumba, Crossfit, Spin, whatever. If you go to a few classes you will find one you like.

The instructors design the class so that you get a reasonable work volume with low risk of injury. For me the instructor always gets me to do more work volume then I would do on my own.

A class is good because you can compare your performance to others that are doing the same thing.

I'm not an athlete, but I've been running 15.3km/day for six days a week for almost a year, and _maybe_ I can put some upper limit on your expectations. While I'm overweight (175cm/86kg, with 75kg being probably the perfect weight for my body type), I am in good shape, and I've been running approximately three times/week, 39km/week for the past 12 years (except the last year).

I don't think an untrained person can go above 500kcal and not feel tired, at least when running. I burn approximately 1100-1200 kcal per session, and from time to time, I do feel tired. It does have an impact on my mental capabilities; hence I do it after work.

A lot will depend on the sport you choose. Burning the same number of calories always felt much more physically demanding when running than when cyclic. Swimming might be the best choice, but it takes much more time than just going for a run/ride. Length and quality of your sleep will also play a big role ( I used to sleep 5h/day, but these days I need around 6h/day to regenerate ). Diet is also important. Plus, the length and intensity of the training session will have a significant impact. Running at 15km/h pace is an order (or two) of magnitude more demanding than running at 12km/h pace.

Be very careful not to overheat and stay hydrated when exercising. From my experience effects of overheating tend to last for hours (if not for the whole day) and have quite a big impact on my mental capabilities and overall feel. It's also not something that I can alleviate or treat successfully once it happens. Sure, a cold shower will bring relief, but it will not get me to 100% of my capabilities, and I will feel tired afterward anyway.

Take into account your shape, weight and age. Don't try to run 7km/day if you're obese, you'll easily get hurt. Swimming, hiking and cyclic might be much better option. Also, start slow, maybe at 20% of your target training session and increase it by 10% every day - see how you feel. Feeling tired is ok, your body will adjust, but if you experience actual pain, cramps, some stiff tendons etc. take a step back.

I am an athlete, but not an extremely fit one. I do cycling, 5-10 hours a week.

On a good weather day, I can leave the house on the bicycle, ride for 2-3 hours at a casual/slightly-brisk pace, and burn as much as 1500 calories in a day. I bring a light snack & a bottle of water, but i don't go crazy with "nutrition" - just a granola bar & water.

Not putting down crazy numbers either, averaging maybe 80 watts / hour for 2-3 hours. I do this once or twice a month.

That doesn't add up. Cycling for 3 hours at 80 watts should only burn about 860 kcal, not 1500.

https://www.welovecycling.com/wide/2020/05/14/how-to-convert...

I went back & looked at my most recent "long ride" this fall to see for sure - and you're right. my avg wattage for this ride is 108 ; 80 watts is what I usually do when riding with someone else, ie socially, so that was the ballpark figure I used.

Losing weight can be surprisingly easy (for most people) by making a few dietary changes and doing some minimal exercise.

1. Lower carb intake to one 'session' a day. Kind of like intermittent fasting, but only for the carbs. Eat as much fat / protein you want the rest of the time. IMO, include 'sugar replacements' in the carb category, even if they supposedly don't have any.

2. 20 minutes of cardio 3-4 times a week. Rowing and elliptical are easy on the joints.

That's it.

Weight loss is about doing the right thing for long stretches of time. It is a war where time in some sense is the turf being fought over. Time spent being unhealthy vs time spent being healthy.

Not really the max power expenditure you can output 30 minutes (and to be charitable, let’s also add the elevated metabolism for an extra 4 hours after) each day.

Does it help? Yes it’s definitely a ~linear multiplier (for “reasonable” amounts of exercise).

As is the time spent doing the right things for weight loss (up to a point: k*e^-t probably models the benefits well up to some approximation bound)

How do you win a fight involving time? Make time the key performance indicator, eg fasting, I am starting to think.

Fasting as opposed to calorie restriction with many meals, bc while they probably reach similar outcomes w similar discipline, there are just a lot more opportunities to screw yourself up w/ calorie restriction than just say “not my eating time” once you get used to it imo

Deuterated water studies show that until you reach Olympic levels of training, you burn roughly the same amount of calories per day whether you exercise intensely or not. Your body simply shunts the available calories to the systems that need them with the highest priority.

This means things like your immune system get shortchanged if you exercise a lot.

If you want to lose weight, the only real way is to reduce caloric intake. The saying is "You can't outrun the fork."

If you want caloric consumption driven by external means--go swimming. Your body must maintain thermal equilibrium and doing so while immersed in cooler water is probably more calorically expensive than the exercise itself. However, the above caveat applies, your body will simply shunt calories around.

I've been on 25-30 mile day hikes. I did fine, got home, and slept really well. I'm in shape, but certainly not an athlete. I was sore the next day, but day after that I might be able to work out.

From here[1], it looks like you might burn ~100 calories per mile walking. That translates to 2500-3000 calories.

1 - https://www.healthline.com/health/calories-burned-walking#ca...

The most common thing for people to do when they first hit the gym is to overdo it and then stop after a few workouts. The difficulty is psychological, not physical. The more painful you make it, the more your lizard brain will revolt. It is possible to have workouts that leave you feeling great. You just have to take it easy at first. I recommend warming up with yoga before hitting the weights.

That said, counting calories is the most effective thing you can do to lose weight.

I am not an athlete. On chest days where I go my hardest (high reps and 80% max) I can burn 550 calories. The following day I'm fine. I don't get sore anymore.

Out of curiosity, how are you measuring your calorie expenditure for these workouts?

Used both an Apple Watch latest and the samsung gear watch latest (I switched to android over christmas). Tracked using their workout watch apps.

> different picture for athletes

Calories burned depend on many factors, so they are basically impossible to predict without knowing at least age/weight/height and more ideally the accurate heartrate during the workout of the person. But nonetheless I'd say that if you are able to perform a single session workout in which you burn >= 1000, I think you deserve the label "athlete" and do not count as a beginner.

I’m not an athlete in the intended sense of the word; like many here, I sit in front of a computer all day. I train Muay Thai however and like to track my activity.

According to my Whoop HR monitor, I burn around 1000-1200 kcal at 170 pounds during an hour long class. Not sure how accurate that is so take it with a grain of salt.

That is almost certainly way too high. As a point of comparison, in order to burn 1200 kcal in an hour of running a person your size would have to cover 11 miles. That would be a major effort for a highly trained sub-elite athlete.

If you want a sanity check on your fitness tracker data you can do a lab test where they sample exhaled gasses to directly calculate energy expenditure rather than inferring it from heart rate.

Yeah I’m sure there is a large margin of error there. Avg HR is around 160 with peak of 190

At that weight and heart rate your actual energy expenditure is probably closer to 750 kcal than 1000. But that's still a solid workout and a lot more than most people do.

I regularly burn 800-900 calories an hour during HIIT workouts. Typically I’m worn out and very hungry throughout the day.

Most I’ve burned was 1500/1600 calories riding a bike with moderate intensity but didn’t feel that bad after.

Fork put-downs are really the only way you’re going to get that sort of deficit.

At my apex, two years ago, I used to run approximately 7 miles everyday on the treadmill in about 70 minutes, I burned 1000+ calories, and I weighed approximately 220 lbs and I am 6 feet tall.

When I first started using the treadmill, it was to lose weight, my starting weight was well over 300lbs.

Currently I have a vaccine side-effect that I can't quite shake, so now I can't run for any appreciable amount; but I still manage to burn about 800 calories on the treadmill mainly by walking at an incline and some short bursts of jogging, throughout I have to rest, where I didn't previously.

To answer your question:

When I was still employed I ran nearly 7 miles a day in 70 minutes one day a week before work -- on an empty stomach -- and because I was intermittent fasting I didn't eat until late in the afternoon. I had a very physical job at an Amazon fulfillment center (warehouse), but I was still able to work throughout the day, without tiring. Albeit, I couldn't imagine, and never attempted to work at Amazon, and then running 7 miles after work.

I was never injured to the point where I couldn't exercise, my joints held up well. When I first started using the treadmill, it was unfathomable to me to even walk one mile on it, I increased my pace everyday, and thus, I was able to build, overtime, quite a bit of endurance, my key was persistence.

The amount of calories burned is based on my intensity and amount of time spent doing the activity. It'd not about being athletic, it's about having endurance. I don't consider myself fit. But I think the day with my most energy expenditure was when I spent a day just walking around New York City, 20 miles in about 10 hours. Both quantities seem like high numbers but the average speed is 2 miles per hour. It's hard to walk that slow intentionally. I had my heart rate chess strap on the whole time and I averaged in the 150s and hit a high of 185bpm when I was rushing to make an dinner with a friend. That is about 1800+ calories burned. But then I have had days when I did 7+ mph for an hour each on a treadmill and elliptical and a 60 minute group yoga class in the middle and my max hr hit 208bpm. I estimated that I spent a minimum of 1200 calories that day. I have had a few months of going to the gym twice a day for 90 minutes each. I am 6'1" and am around 230lbs, 25%+ body fat. I am not fit, I can't run a mile at more than a jogging speed without getting tired.

I realized that I will need time to get to athlete level performance so instead I focused on the endurance.

I would say hitting 600 calories in 90 minutes is possible by everyone that's fit enough to walk/jog for that amount of time, a minimum average of 4.0 mph and at least 30 minutes at above 6.5mph. Being a non-athlete would mean you take 15+ minutes walk/rest between each 10 minute jog.

I can comfortably say even now, after I took a long break from working out due to covid, I can do a 30 minute class/jog then do 30 minutes in the evening and over 2 weeks work my way back up to 90+30. An hour of intense activity is 400+ calories as long as it's a cardio/high repetition centered session.

To answer your question, I think a 90 minute session with 600+ is reasonable and then 200+ calories in a 30 minute evening session. The evening doesn't have to be intense, it could be stretching and yoga so you reduce the risk of injury. Yoga might need to be closer to an hour though because it might be harder to hit 200+ calories in just 30.

The difference between the actual calories burned and your goal of 1000 can be made up by taking care of your diet. 200 Calorie deficit with 600 calories burned during a workout is a sustainable lifestyle.

Some people say that exercise isn't the solution to weight-loss but I think that isn't completely accurate. If you work out intensely, you will feel more hungry and your diet would get worse even if you feel like you are eating the same amount. Diet without exercise feels so draining because you don't feel any sense of accomplishment from not eating, just hungry. Accomplishing goals of working out longer are measurable.

Walking at 2 mph shouldn't cause a 150 bpm heart rate in a healthy adult. Either your heart rate monitor was faulty or there's something wrong with your cardiovascular system. There's a lot of normal individual variation in heart rates but seriously 150 for casual walking is abnormal.

There wasn't a moment in time where it was casual walking at exactly 2 miles per hour, I was simply describing an average if you consider the total distance over total time.

I was also going up and down a lot of elevation and stairs on that day. I think you would agree that walking up stairs would sufficiently elevate your heart rate to 150+ bpm easily even if you are going slower than 2 mph.

Thank you for your concern though. I had an EKG done at my annual physical and spoke with a medical professional about how my maximum heart rate has been 218 bpm during a specific gym session, no caffeine or other stimulant use. I use a polar h10 with the pro strap and have seen 210+ over multiple gym sessions. He said don't worry about it. Resting heart rate and how quickly you return to your resting heart rate after exercise is the main measures of health and fitness. And just to be clear, pushing myself to a very high heart rate was very much intentional, I was very aware of my breathing and watching the reading on a second by second basis and not pushing myself to any sort of injury. I was able to do yoga that evening and do a less intense 90 minute workout the next day. Pushing myself in that way isn't a thing I do regularly.

https://imgur.com/a/yfV8FYc As you can see it's relatively smooth as it's over an hour, no sudden spikes in my heart rate. This was on a stationary bike. This was recorded on a different day, not the 20 mile day. 150/218 puts 150 at 69% which is comfortably in the aerobic/light HR zone for me. I calculated my max HR to be 2.6 standard deviations away from the average based on https://www.sciencedirect.com/science/article/pii/S073510970... .

My resting HR is in the mid 60 to low 70 but has been creeping up over covid since I stopped exercising. I guess the average person doesn't have as high of a max HR and so the 150 would be off. For most people beginning their fitness journey, worrying about HR zones is pretty far down on the list of priorities.

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