I write a lot about nutrition and the benefits of lifting weights, but rarely touch on the subject of cardio. There are reasons for this:
1.I do not find cardio to be enjoyable.
2.Weight training has provided me with far superior results, both physically and aesthetically.
3.Weight training allows me to eat like a madman in the hours following a session at the gym.
As I wrote in an older post, in my opinion, there are only three reasons to do cardio:
1.You LOVE it.
2.You are trying to burn excess calories, in an attempt to lose fat.
3.You are training for a race/sport.
This is because in my opinion, based on research and personal experience, the most effective ways to improve body composition (read: lose fat, appear leaner) are as follows:
1.High-intensity weight training (read: lifting heavy things)
2.Weight training intervals
3.High-intensity cardio intervals
5.Low-intensity weight training (otherwise known as sitting around at the gym and accomplishing next to nothing)
Note: For pure weight-loss of both muscle and fat in an attempt to get skinny-fat, low-intensity cardio would be a top choice
As with anything else in life, the harder you work, the better your results will be (shocking, I know). High-intensity cardio intervals (followed by extended steady-state cardio) almost surely burns the most calories/fat during the exercise -- although it's possible that weight training intervals, if done hard and long enough, can match or exceed the results of cardio. However, the body will continue to burn calories after any workout, and it is the type and intensity of the workout will determine the length and strength of this extra calorie-burn. Studies have shown that after cardio, the body tends to burn calories at an elevated rate for 30-60 minutes; maybe up to 2 hours if you really overdid it with intervals. After weight training, the body can burn calories at an elevated rate for days. Additionally, weight training builds muscle whereas cardio builds very little. More muscle equates to a higher metabolism. A higher metabolism equates to more calories burned in a resting state. I was never a great math student, but it's not difficult to see how weight training trumps cardio in the realm of fat burning.
In case you'd like a more scientific explanation: Growth hormone (GH) and testosterone (T) are the two primary anabolic (muscle-building) hormones in the human body. When the levels of these hormones rise, muscular size and strength will increase. These hormones are also lipolytic, meaning they stimulate the body to burn stored fat for fuel, so a rise in these hormones actually leads to a reduction in overall body fat as well. GH and T are difficult to manipulate, but weight training can elicit a small rise in both hormones; cardio does not. As a matter of fact, it is likely that you must specifically perform heavy, compound weight-training exercises to really benefit from any kind of hormonal response (read: you must perform exercises like the squat, deadlift, push-press, etc. at a high intensity to elicit any hormonal change). Strength training also increases the body's insulin sensitivity, which means that post-weight training, the body will selectively shuttle carbohydrates and other nutrients to the damaged muscle cells instead of fat cells for storage. This is not the case (at least not to the same degree) with cardio.
My friends over at Precision Nutrition recently released an article on this exact topic. Their findings? That with cardio programs, individuals lose fat and improve their cardiovascular fitness and health, but lose muscle mass in the process. With weight training programs? Individuals lose fat and equally increase their cardiovascular fitness and health, but also increase their strength and gain muscle.
Although the benefits of weight training are quite clear, the "perfect" exercise plan would likely include both weight training and cardio (as usual, balance is pretty much always the key). Cardiovascular exercise in itself is very beneficial -- aside from burning fat it also helps to improve glucose metabolism, lower resting heart rate, and lower blood pressure and cholesterol. You can also do cardio every day, as it is much easier to recover from than an intense weight-lifting workout. If you are doing cardio and weights on the same day, I would highly recommend doing your weights first -- this will ensure that you have the most energy possible for weights, which should encourage good form and reduce the risk of injury, not to mention put you in a better position hormonally (if you do cardio first, your catabolic cortisol levels will be elevated when you begin weight training, which is the opposite effect that you want). If your goal is to burn fat, start with a major compound movement (squat, deadlift, overhead press, etc.) to stoke the engine and then hit some intense intervals for great results. The only exception would be if you are training specifically for strength. In this scenario, either do your cardio first, or better yet, do it on another day. Cardio after heavy lifting will not have any benefits to those looking to get stronger; if anything, it will wipe out the progress you just made. If you are going for strength, just smash your weights, and immediately eat some food.
A few other cardio tips:
- Do your cardio on an empty stomach. If you do cardio after eating carbs, you will burn those instead of stored fat.
- If you are a big believer in caffeine like I am, or if you take fat-burners, take these supplements roughly 30 minutes prior to your cardio to enhance your work capacity and increase your pain threshold. It will increase you metabolism and enable you to push yourself harder; both of which should result in more fat burned.
- My ideal cardio? Around 40 minutes, first thing in the morning, after "eating" nothing but a coffee. This is capitalizing on a great fat-burning state and will kick-start your metabolism for the day!
So although I prefer the efficiency and results of weights over cardio, doing any sort of physical activity is better than nothing, so find something you love to do and do it to the best of your ability; but keep the hierarchy above in mind, and try to pick the most efficient activity for your personal goals. The key, no matter what the exercise, is to push yourself as hard as possible. Make yourself sweat. Lose your breath. And try to introduce your body to a new kind of stimulus on a regular basis -- only then will the body be challenged to make adaptations and in turn work a bit harder than before.