Cardio can help with weight loss, but cardio is not a mandatory condition for losing weight. Cardio training raises heart rate, uses energy, and can support fat loss, but the key factor in weight loss is spending more calories than you consume.
Cardio training is physical activity aimed at strengthening the cardiovascular system and improving endurance. Cardio training includes running, cycling, swimming, dancing, brisk walking, and even housework done at a fast pace for at least 30 minutes.
The short version
- Cardio training is activity that strengthens the cardiovascular system and improves endurance.
- Cardio can support weight loss by increasing energy use during exercise, but weight loss depends on a calorie deficit.
- Low- and moderate-intensity cardio uses fat as a main energy source more often than high-intensity cardio.
- Strength training and cardio work differently, and combining both is presented as the best option.
- Cardio can be done on a separate day or after strength training, and a short 15–20 minute session after strength work can be enough.
What is cardio and why do it?
Cardio training is a type of physical activity aimed at strengthening the cardiovascular system and increasing endurance. During cardio training, pulse rate rises, heart rate increases, and the heart pumps more blood, which trains the heart muscle.
WHO recommendations say that an adult should devote 150 minutes a week to physical activity. Cardio training can be one way to reach that amount of activity.
Research cited in the source says that cardio loads may help lower cortisol levels, strengthen blood vessels, and have a positive effect on bowel function. Cardio training also contributes to improved mood and lower stress levels through the production of endorphins.
Cardio includes running, jumping rope, cycling, swimming, dancing, brisk walking, and even cleaning. A good target is activity lasting at least 30 minutes at a brisk pace, so cardio does not require a fitness club and can also be done at home.
How does cardio work for weight loss?
Cardio works for weight loss by increasing breathing and energy use during exercise. During cardio training, the body actively and deeply breathes, oxygen intake rises, and the body uses energy stored as glycogen and fat reserves.
At the beginning of exercise, the body mainly uses glycogen stored in the muscles and liver. As the load continues and remains long enough and intense enough, the body shifts energy sourcing and starts taking more energy from fat reserves.
Calorie burning slows down after exercise ends. Energy expenditure during cardio still does not replace the main rule of weight loss, because weight loss depends on spending more calories than you consume.
What types of cardio are there?
Cardio training is divided by intensity and focus. The source describes low-intensity, medium-intensity, and high-intensity cardio.
- Low-intensity cardio is performed for a long time, usually 30–60 minutes. Low-intensity cardio includes walking, easy cycling, and climbing stairs.
- Medium-intensity cardio is done at a steady moderate pace. Medium-intensity cardio includes jogging, fitness aerobics, and training on an elliptical machine or stepper.
- High-intensity cardio is mainly interval training, where short maximum effort alternates with rest or lower effort. High-intensity cardio includes sprints, jumping rope, cycling classes, and circuit training.
What are heart rate zones?
Heart rate zones show how the body uses energy at different exercise intensities. Heart rate zones help indicate whether the body is mainly burning fat, improving endurance, or training speed and strength.
The heart beats at different rates depending on how hard a person is working. Heart rate zones divide that range into levels so the effect of physical load on the body becomes easier to understand.
How do you calculate your heart rate zone?
Heart rate zones are calculated from maximum heart rate. The standard formula in the source is: for men, maximum heart rate = 220 minus age, and for women, maximum heart rate = 226 minus age.
A 40-year-old man, for example, would have a maximum heart rate of 180 beats per minute by that formula. Heart rate zones are then calculated as percentages of that maximum value.
Which heart rate zones are used for cardio?
The source identifies 5 heart rate zones. Each heart rate zone corresponds to a different type of effort.
- 50–60% of maximum heart rate is the recovery or wellness zone. The recovery zone appears during yoga, easy walking, or stretching, and is usually tracked during rest and recovery after the main workout.
- 60–70% of maximum heart rate is the fat-burning zone. The fat-burning zone allows long training duration, which is why fat breakdown occurs there, and examples include an elliptical, a stepper, or light running.
- 70–80% of maximum heart rate is the aerobic zone. The aerobic zone is suitable for people who want to strengthen the heart or become more enduring, and examples include long-distance running, cycling, and group classes.
- 80–90% of maximum heart rate is the anaerobic zone. The anaerobic zone is high-intensity work for experienced athletes aimed at developing strength and speed, mainly through short but very intense loads such as intervals, sprints, and strength work.
- 90–100% of maximum heart rate is the maximum zone. The maximum zone is used in training by professional athletes and mainly in competition-level loads, and the source says unprepared people should not do such training without medical permission.
Low- and moderate-intensity work such as jogging and walking mainly uses fat as an energy source. High-intensity work such as sprinting and interval training relies more on carbohydrates, meaning glycogen.
How can you measure your pulse?
Pulse can be measured with sports watches, chest heart rate monitors, and cardio sensors. Pulse can also be measured manually in a simple way.
The simplest method is to find the pulse on the wrist or neck, count the beats for 15 seconds, and multiply the number by 4. That method gives the pulse rate in beats per minute.
What is better for weight loss: cardio or strength training?
Both cardio and strength training are effective for weight loss, but cardio and strength training work differently. Strength training is aimed at building muscle mass and shaping body proportions, while cardio allows calorie burning during the session itself.
Strength training creates mechanical overload in muscles, which raises energy needs for recovery, and muscle tissue requires more energy to maintain than fat tissue. More muscle means more calories burned even after exercise ends.
Cardio training helps burn calories here and now. Cardio training also engages the lymphatic system, so excess water leaves the body and swelling is reduced, although the source notes that swelling should not be confused with fat.
The source includes a medical note saying that true edema with a medical cause has a specific location. The source says edema linked to cardiovascular system or vein diseases usually affects the feet and lower legs, while edema linked to kidney diseases affects the lower legs and veins.
Cardio without additional strength training may lead to loss of both fat mass and muscle mass. The source says the ideal option is to combine both types of training.
Can you do cardio after strength training or on a separate day?
Cardio can be done on a separate day or after strength training. The choice depends on physical fitness and on whether a person has enough time.
Separate days increase total physical activity and combine loads that do not conflict with each other. A combination in one session is also allowed if a person feels well.
The trainer quoted in the source says that if cardio after another workout is more convenient, the main principle is not to overdo it. The trainer quoted in the source suggests 15–20 minutes on a cardio machine after strength training.
Balanced eating with a correct calorie deficit, along with sleep and overall lifestyle, remains the most important rule for weight loss regardless of the type of exercise. Cardio does not replace that rule.
Common questions
Do I have to do cardio to lose weight?
Cardio can help with weight loss, but cardio is not required for weight loss. Weight loss depends on spending more calories than you consume.
Which cardio burns fat best?
The source says the 60–70% maximum heart rate zone is the fat-burning zone. The source gives the elliptical, the stepper, and light running as examples for that zone.
Is cardio or strength training better for weight loss?
Both cardio and strength training can be effective for weight loss, but the two types of training work differently. The source presents combining cardio and strength training as the ideal option.
Can I do cardio after lifting weights?
Cardio can be done after strength training if that format feels convenient. The source suggests keeping post-strength cardio moderate and limiting cardio machine work to 15–20 minutes.
How do I check my pulse without a device?
Pulse can be checked by finding the pulse on the wrist or neck. Count the beats for 15 seconds and multiply the number by 4.