I like to do cycling and I want to lose weight through cycling. But my friend told me about cardio instead of cycling, since cycling burns calories at a much slower rate. Is it true? So what's better to lose calories faster, cycling or other exercises?
The answer to the Title question, "Is cycling an aerobic or anaerobic exercise?", is yes.
Aerobic exercises are endurance-type exercises that increase a person’s heart rate and breathing rate over relatively long durations. Anaerobic exercises are exercises that involve short bursts of intense activity.
— Aerobic vs. anaerobic exercises: What to know
Taking a long ride will provide aerobic exercise. You'll be burning more energy than usual, and will be continually breathing faster than usual in order to maintain a consistent level of oxygen in the blood.
If during that ride you occasionally have a quick sprint or a short steep climb, so that when it's over you find yourself needing to stop and breathe very heavily, it's anaerobic. The oxygen in your blood will be briefly and temporarily depleted.
As for your purpose, in general, exercise by itself is not a good way to lose weight. Exercise does burn calories (about 10 per minute for moderate cycling), but for most people the major effect of this is that they end up feeling hungrier afterward, and often end up eating more calories than what they just burned.
Exercise is a good thing, and given what site this is, obviously cycling is the best form of exercise, but it should be used in conjunction with other methods of weight loss.
The exercise that really loses weight is the exercise of restraint.
Eating because one feels hungry is a great way to gain weight, not lose it.
Following exercising, one will feel hungry, and that is good. It is proof that some fat has been burned, and the body is simply saying that it needs to be fed so it can refill the fat cells. To act on that request will simply restore any weight that was lost due to the exercise, and perhaps some more.
Most people, especially those that are overweight, will be exhausted after 45 minutes of moderate cycling. But in terms of weight, they could have lost twice as much simply by not eating a Big Mac Meal and feeling hungry for a few hours.
In fact, the general rule is that the most effective way to lose weight is to feel hungry.
Exercise is great for strong bones, better endurance, and more effective respiratory and circulatory systems. But it should not be seen as a quick and easy method of weight loss.
And always avoid fructose. It is the one carbohydrate that doesn't "spoil your dinner". It has an extremely low glycemic index and can take hours before it might be converted to blood sugar (dextrose), though by then it is more likely to have been stored as fat.
(Long distance cyclists might want to take the opposite advice.)
Cycling at moderate intensity is mostly an aerobic cardio exercise.
How many calories you burn in an hour depends on your power output. A heavy professional cyclist (90kg,
6W/kg 5W/kg) can probably burn around 2000kcal in a single hour when cycling all-out. For an amateur at a less-than-all-out intensity it’s more like 500–1000kcal in an hour.
Other cardio exercises like running or rowing have similar rates.
In my opinion cycling has several advantages for burning calories:
- Even complete beginners can do it for >30 minutes. With a bit of training two hours are very achievable.
- Risk of overuse injuries is low and time for recovery is short. If you don’t push too hard even an amateur can go cycling for a meaningful duration every day.
- The above two points are partly possible because intensity can be adjusted in a wide range thanks to gear shifting.
- With a power meter you can measure calories burned pretty accurately.
- You can integrate it into your daily life. Commuting, shopping, visiting friends or family, going to a restaurant … many of those activities require travel in a 5–25km distance which is ideal for cycling, even for a beginner.
That being said, there is no magic recipe for burning calories. If you are consuming 3000kcal every day, are unwilling/unable to reduce intake and still want to lose weight you’ll simply have to exercise for more than an hour every day. And that hour of exercise can be negated in 5 minutes by eating two big chocolate bars.
You have several questions mixed into one here. You're asking about "losing calories", and about losing weight. Those are two different things. You also ask if cycling is aerobic or anaerobic, and if cycling is the best option for losing weight. Those are all different questions.
Burning calories, and aerobic vs anaerobic exercise
You are constantly burning calories. Even sitting still, you're still burning calories as your heart beats, your lungs inhale, and your body does everything it does to keep you alive. All those things require energy, which your body obtains by burning calories. There are several different ways in which your body burns calories, depending on what you're doing.
During aerobic exercise, you are using slow-twitch muscle fibers. Aerobic exercise is less focused on intensity and more on length, such as a long bike ride. Slow-twitch muscle fibers burn calories using your stored fat reserves and the oxygen in your blood, along with small amounts of glucose (sugar).
During anaerobic exercise, you are using fast-twitch muscle fibers. Anaerobic exercise is faster-paced and much more intense, such as sprinting. Fast-twitch muscle fibers burn the glucose in your blood stream, and leaves lactic acid in the process, causing that muscle burn that occurs when sprinting.
Both of those methods are burning calories.
Anaerobic exercise burns calories faster, since you're burning through all the sugar in your bloodstream. However, you do need to resupply the calories that you're burning. If you use too much of the glucose in your bloodstream, you'll experience exhaustion and fatigue, due to not having any fuel left to burn. Remember, aerobic axercise also needs small amounts of glucose to function. You need to refuel, with carbs and sugar, often when doing anaerobic exercise or risk hypoglycaemia (low blood sugar), a dangerous condition.
Aerobic exercise burns calories more slowly, but does so from your fat reserves as well. Consuming carbs before and during aerobic exercise is recommended, in order to maintain your glucose levels. If you don't eat beforehand, your body automatically goes into preservation mode; you won't burn fat, because your body is making sure to not burn too much because it hasn't had anything, and is trying to make sure you don't starve. If your goal is to burn fat, eat and drink before and during an aerobic session; less so afterwards.
Cycling can be both aerobic and anaerobic. Whether your ride is predominantly one or the other depends entirely on how you're riding that day, as well as what discipline you're riding. Road cycling tends to be much more aerobic, with long days in the saddle spending hours on end pedaling. Mountain biking is often much more anaerobic, with lots of short sprints to get up small hills, perform jumps, get over bumps, etc. It all depends on whether your specific training ride is designed more for an aerobic session or anaerobic session.
Is cycling the best option for burning calories? It's hard to say. Other sports are more or less demanding on other parts of the body, while cycling is very legs-focused. It's possible that other sports that move more of the body - such as swimming - may be more efficient at burning calories than cycling. Hoever, it is hard to beat cycling when it comes to aerobic sessions; most sports are quite difficult to maintain for six-plus hours, while it's quite doable to maintain that on a bike.
Ultimately, any exercise is going to burn more calories and more fat than not doing anything. Pick a sport that your enjoy, and work on it - that's more important than the exact count of calories you're burning doing cycling vs other sports.
Information in this answer is based on my personal experience as a competitive rider for several years, as well as information I recieved when doing my coaching certification in 2019.
It really depends on the effort you are making. If you produce power, the body must burn some energy storage, quick ATP, blood sugars, then later finally body fats. If your effort on the bike is higher then when doing other cardio activities, you should burn the body fats faster, but you first have to get into the fat-burning regime. That takes some time for all activities.
Normally, cycling is definitely an aerobic activity.For short burst and speeds it can also be anaerobic, but only for short time intervals with very increased effort.
One point that others haven’t covered. Cycling is low impact, and thus it’s comfortable to do it for longer than running. Cycling can be engaging, i.e. it’s very different from an exercise bike, treadmill, or rowing machine in the gym, so it can be pleasant and mentally engaging to do it for longer periods than those activities. Because it is possible and pleasant to do it for prolonged periods, it can be better than other exercises for weight loss.
Naturally, the trade off is that burning more calories takes more time, and you have some barriers to entry in terms of needing to get equipment and relevant skills, e.g. riding, navigating, basic repairs.
It's quite easy to know if an exercise is aerobic or not, but first a bit of physiology.
First, your muscles contain various types of fibers: slow fibers for long sustained low intensity effort, and fast fibers for short bursts of high-intensity effort.
These are exercised and developed differently by different types of efforts: basically, your body will become better at doing what you do often. If you only run marathons or only do long bicycle rides at moderate speed, you will train your slow twitch fibers for endurance and you will look like a marathon runner. If you only do sprints, then you will get huge fancy muscles, along with some endurance, but not as much as you'd hope, and the guy with the spindly legs will leave you in the dust on climbs.
Second, your muscle cells get their energy from tiny powerplants called mitochondria which burn fat, glucose, and other stuff.
Mitochondria use a range of chemical pathways to burn fuel, they may use several pathways at the same time, but they prioritize the most efficient one depending on what fuel is available, and how much oxygen they get.
The most efficient is aerobic metabolism: burning fuel using oxygen, which exploits all the energy in the fuel and degrades it down to water (which is recycled) and carbon dioxyde (which you breathe out).
The absolute best is burning glucose, it has higher power throughput than burning fat, so glucose has priority over fat. This has an interesting side effect: if you eat a lot of sugary things before exercising, your mitochondria will be very happy to burn it, and they won't use any fat.
The amount of aerobic power you can produce depends on how much oxygen your body can transport to your muscle cells. If you exceed that power, all the oxygen is used up as fast as it comes in, and the excess power is produced by converting glucose into lactic acid without oxygen. This can produce huge power, but the lactic acid accumulates which manifests as a burning sensation in your muscles. When that occurs, it doesn't mean you're over the limit, rather it means you've been over the aerobic limit for a while already. If you keep going, lactate will keep accumulating and you will either stop or throw up.
Just think of a video game: anaerobic is your stamina gauge. It has a certain capacity, it is consumed when you sprint, and when it runs out, your power drops significantly.
Meanwhile, your aerobic capacity is the amount of effort you can sustain at a constant level for a long time, say longer than one hour.
So, to answer your question. Since "effort level" is subjective, let's use an objective measurement instead: time.
A power level you could sustain for many hours: aerobic, burning a mix of glucose and fat. This is pleasant, not really taxing, and if you do it for an hour you arrive feeling good, rested, it doesn't feel like exercising.
A power level you could sustain for 1-2 hours: aerobic, burning mostly glucose.
A power level you could sustain for a few minutes or less (sprinting): aerobic glucose + anaerobic glucose.
When you run out of glucose, power output drops significantly ("hitting the wall") which is not fun, and sprinting is almost impossible.
After sprinting, when you slow down to recover, more oxygen becomes available to recycle all the produced lactates back into pyruvate and glucose. So your thighs stop burning and you feel better without all that lactate. If you don't slow down enough, and stay at the aerobic limit even after a sprint, then all the oxygen is used up to produce power and lactates are not recycled, so your thighs keep burning. If you slow down too much (or stop) then your breathing and heart rate will slow down and lactate recycling will be slower. The optimum seems to be the most pleasant, leisurely pace.
So one important thing is when doing "anaerobic" high intensity interval training (aka sprinting between traffic lights), the cooldown period after the sprint is part of the exercise! During this cooldown your body must either recycle all the lactate that was produced or use it as fuel. Recycling it uses energy and oxygen, so every anaerobic effort is followed by aerobic metabolism to clean up the mess. Anaerobic effort doesn't burn any fat, but the cooldown can burn fat. Later, at home when you rest, you will notice elevated heart rate for several hours because your body is working to replenish glycogen stores, build new muscle, etc.
So, basically, to burn the highest percentage of fat in proportion to the total fuel your body will use, you must ride at a moderate effort level for a very long time. This works but it is not convenient as a weight loss mechanism because you need to spend the whole day on a bike. It is only practical if you do a long bicycle trip. Also the effort is low, so while your body is using more fat than glucose, it is not burning a lot of energy.
The most important thing about exercising is to actually exercise, and in order to do that, it should be fun and pleasant, which means it should be varied and/or practical. If you ride fast, slow, uphill, downhill, with a good mix of cardio, sprints, cooldowns, eat a bit of sugar but not too much, a bit of high glycemic "slow" sugar but not too much. One day a big mountain, the other day lots of small hills, sprints between traffic lights, set yourself challenges, go with friends, etc. The goal should be to get back home well exercised but not entirely exhausted. Then your body will work at elevated metabolism for many hours and burn more fat while you do nothing at all (this requires not eating a huge feast after the ride).
Now about your "knowledgeable" friend:
If you keep your heart rate on the "cardio" range on a bike, you're doing cardio. What makes it cardio is when you keep your heart rate in a specific range for a long enough amount of time, it doesn't matter how you do it, push-ups, cycling, walking uphill, running, whatever. If you want to do it with your arms, you're gonna need pretty big arms though.
For example when the weather doesn't allow cycling, I do cardio by walking up a hill. 300m altitude in 20 minutes is 15m/min, at 100 kilos, about 250 watts, then I walk down.
In fact the only way to do cardio is outside, not in an overheated gym.
If you have any kind of decent leg power output... say, you produce 200 Watts power output on your bike, you will also produce 800 Watts of heat, that's as much as a small electric heater. Outside, you get free air cooling, but to survive this for any length of time indoors, you need a big fan unless the aircon is set to a temperature that would make everyone who isn't doing cardio freeze and leave the gym. In the usual gym which is heated to more than 20°C, forget it. You will overheat, sweat buckets, and exercise at a much lower intensity that you could.