You may feel like your weight lifting could use something extra. Find out what the effects will be of doing 20 minutes of cardio after your weights session.
Most people lift weights with the goal of growing their muscles so the first thing to note is that being in a calorie surplus and consuming enough other nutrients are generally recommended if you are trying to achieve this.
If the 20 minutes of cardio after lifting weights makes consuming enough nutrients too hard to achieve, it could interfere with your muscle growth goals.
That being said, for people who do not have this concern, 20 minutes of cardio after resistance training can help reduce fat gain (or even cause fat loss), strengthen your cardiovascular system, improve sleep, etc.
Something you do want to keep in mind is that these 20 minutes are likely not enough to hit most cardiovascular exercise recommendations.
If it aligns with your training goals and schedule, you could consider implementing more, longer, and/or more intense cardiovascular sessions.
Cardio before or after weights
First of all, many people are interested in working more on their cardiovascular health but they are not sure whether they should do this before or after lifting weights.
Besides maybe a short cardio session to warm up certain muscles, it is generally recommended to keep your cardiovascular exercise for after weights.
The main reason for this is that doing cardio before your resistance training exercise could reduce lifting performance.
Since you really need to be able to challenge your muscles enough during the resistance training, you generally just don’t want to run this risk.
It is true that lifting weights will also likely reduce your performance in your cardio workout.
However, you should still be able to reach intensity levels that are required for fat loss, cardiovascular health, and other benefits that will be described later.
Is 20 minutes of cardio after weights good or bad?
Once you have decided to keep your cardiovascular exercise for after your resistance training, you may wonder if durations like 20 minutes are good, bad, and even worth doing.
For people trying to grow their muscles, the main concern with doing any amount of cardio on top of their lifting routine is consuming enough nutrients.
More specifically, being in a calorie surplus seems to be beneficial for muscle growth (1). Since cardio exercise can burn a good number of calories, this is something to keep in mind.
So 20 minutes of cardio after lifting weights can be bad for muscle growth if you don’t compensate with enough nutrients. The main nutrient to keep in mind is calories.
Here are some rough estimations for how many calories a 185-pound (83.25 kg) person burns with 20 minutes of different types of cardio (2):
- Walking (3 mph = 4.8 kmh): 102 calories
- Rowing machine (moderate effort): 140 calories
- Bicycling (12 mph = 19.3 kmh): 233 calories
- Swimming crawl (medium speed = 50 yards/minute): 242 calories
- Running (6 mph = 9.7 kmh): 286 calories
If you don’t have any issues with consuming enough nutrients, it can definitely be worth doing cardio after lifting weights due to the extra physical and mental benefits you get.
While beneficial, just doing 20 minutes of cardio a day is even generally not enough to hit many exercise guidelines for optimal health.
If your body can deal with it and you can eat enough to compensate, you could even consider doing longer cardio sessions after weight lifting like 30 minutes or even an hour.
Benefits of 20 minutes of cardio after weights
Before implementing this extra routine to your workout plan you may want to know about some of the more specific benefits of doing cardio after weights.
These can help you realize the importance and motivate you to keep going after an intense resistance training session.
Can help you lose more fat
Excess body fat causes a variety of negative effects on human health and many people don’t like the way it looks. That is why losing weight, more specifically losing fat, is such a popular fitness goal.
As mentioned above, some individuals struggle with eating enough calories and other nutrients to enable muscle growth.
At the same time, many people also have the opposite issue. They tend to overeat calories which may not interfere with muscle gains but can add unhealthy amounts of body fat.
Besides making changes in other lifestyle areas like nutrition, another way to avoid this is adding cardio exercise after your weight lifting sessions.
As you can see in the calorie-burning estimations above, what cardio exercise you choose and at what intensity you do it can make a big difference.
The best cardio workouts after weights for fat loss typically include running, cycling, rowing, and using a StairMaster at high intensities.
Your cardiovascular system can become stronger
By definition, cardio exercise is a category of activities that mainly work your cardiovascular system which includes your heart, lungs, and blood vessels.
These body parts are responsible for absorbing oxygen from the air and moving the oxygen, nutrients, and waste products to the right places.
When moving more intensely with activities like running, cycling, rowing, etc, the things above need to happen to a larger extent. To do this, your cardiovascular system has to work harder.
Similar to many other body parts, challenging your cardiovascular system enough (but not too much) can strengthen it over time. This is beneficial because it reduces your risk of a variety of related conditions (3, 4, 5).
You could sleep better
Most people already know that enough quality sleep is important for general health, mood, and even building muscle. However, not everyone knows how to improve their sleep.
Something to keep in mind is that overtraining could also lead to the opposite. However, for many people doing 20 minutes of cardio after lifting 3 times a week or something similar should be fine and benefit sleep.
Could improve your cognitive performance
Adding extra cardio after your strength training routine could also improve areas of your life besides physical performance.
First of all, exercising seems to reduce the risk of diseases like Alzheimer’s that involve cognitive decline (9).
Better brain plasticity is generally considered to be helpful for learning things faster, seeing the connection between things faster, and remembering things better.
There will likely be a point where overtraining causes the opposite.
However, most people could see improvements in things like job performance, academic performance, etc. in the long term by adding 20 minutes of cardio to their lifting sessions.
Your mood may improve
The health of your body and the things you do can have an impact on your mood.
By adding 20 minutes of cardio to your lifting sessions, you could reduce the risk of conditions that make you feel bad.
Your regular resistance training routine will also do this to some extent but adding some extra cardio can improve your mood even more.
Can improve general health and longevity
Lastly, getting enough cardiovascular exercise simply improves your general health and longevity through a variety of known and unknown mechanisms.
Even if living longer does not interest you, you likely do not like being sick.
How long should you do cardio after weights?
By now it is clear that adding cardiovascular exercise to your workout routine can offer valuable health benefits.
The question then becomes whether 20 minutes after weights is enough or whether you should do longer cardio sessions.
The Office of Disease Prevention and Health Promotion recommends the following amounts of exercise for adults (19):
- Moving more and sitting less throughout the day
- At least 150 to 300 minutes of moderate-intensity aerobic activity or 75 to 150 minutes of vigorous-intensity aerobic activity a week. Preferably spread throughout the week.
- You can gain additional health benefits by engaging in physical activity beyond the equivalent of 300 minutes of moderate-intensity physical activity a week.
- Muscle-strengthening activities of moderate or greater intensity that involve all major muscle groups on 2 or more days a week.
So even if you would lift weights 7 times a week (which is often not recommended), just doing 20 minutes of cardio after resistance training would not be enough to reach these guidelines.
If optimal health is your goal and you can consume enough nutrients, more cardiovascular exercise could be helpful.
At the same time, these recommendations are not all or nothing. When it comes to health, only adding 5, 10, 15, or 20 minutes of cardio will generally already be better than zero cardiovascular exercise.