Is Cardio Good For Fat Loss?
People often think that you need to do cardio workouts to lose weight. This post is about why you do not HAVE to do cardio to lose fat.
The reason most people want to lose fat is for;
The most common form of cardio is called steady state, for example running on a treadmill is normally steady state and low intensity.
This post will outline why cardio might not be the best course of action for fat loss.
Steady state cardio outside of a gym is most often jogging at a constant speed over a long period of time and distance. This 'training' is thought by some to be best for 'burning calories.' But this could be too simplistic a view when compared to the benefits of lifting weights or resistance training.
An hour of cardio tends to burn more calories compared to an hour of resistance training. (ref 1) But it's not addressing the goal. The target is getting the body to change and adapt long term and for the body composition to change. You need to focus on what happens over 24 hours a day, seven days a week and when that is considered then it seems resistance training is much more beneficial.
It can improve endurance. The reason your endurance improves when you run or why you get stronger when you lift weights is that the body recognises the stress you are placing the body under and the CNS (central nervous system) will instruct the body (muscles, heart, lungs, joints etc) to adapt. So the body will get better the next time you apply the same stress.
The body adapts in so many ways, it adapts when the sun hits your skin, the body makes the skin darker (tans) so you can be in the sun and not burn. It's called adaptation.
Cardio can burn more calories than lifting weights WHILE you are doing the cardio workout. Your body adapts so you get better at cardio but you do not burn more calories while you are NOT doing cardio whereas you see increased calorie usage after you finish a weight training session (ref 3)
Cardio does not require much strength, in fact LESS MUSCLE makes you BETTER AT CARDIO. Endurance training (cardio) also makes you more efficient at burning calories slowly so you use less calories over time. Essentially you're training your metabolism to slow down. (ref 4)
So the chronic adaptation, the training response, to cardio is to burn less calories all the time. You've successfully slowed down you metabolism. You do lose fat but you also lose muscle mass.
You now have to eat less food to maintain your weight as you've lowered your metabolic rate.
You've not even lowered your body fat percentage as, for example, you may have lost 5lbs of fat and 5lb of muscle.
You've made yourself smaller and weaker.
You've reduced the amount of muscle you have and this is the human tissue that is great at improving insulin sensitivity when you have a lot of it. Muscle tissue also burns a tremendous amount of calories. (ref 2)
Resistance training on the other hand
Using resistance designed to build muscle.
Training my body to get better at lifting weights. This means I need more muscle, more strength.
A side effect of this is a faster metabolism and an improved insulin response.
Weight loss might be slower, you may lose fat and build muscle
Scale doesn't move much but body composition changes.
Muscle takes up one third less space than fat of the same weight.
So you could weigh the same but be smaller.
Metabolism speeds up 24/7, you don't need to actively try to burn calories.
Three times a week seems good enough for most people.
Cardio can see deleterious changes in progesterone and estrogen, cortisol can spike and growth hormone can lower. Resistance training does the opposite. When it increases testosterone it also improves receptor function. It balances out progesterone and estrogen. Improved growth hormone level and better cortisol response. Endurance training can lower testosterone in men. (ref 5)
Why is resistance training doing this?
Because it is a 'pro tissue' form of exercise whereas cardio is anti tissue activity.
To build tissue you require anabolic hormones.
To build muscle requires better insulin sensitivity, it requires progesterone and estrogen to be at a correct ratio. It also requires adequate levels of growth hormone.
Reducing muscle requires less testosterone, less growth hormone.
So if your target is to get youthful levels of these hormones then resistance training sets you up the right way.
You can also eat more food!
Hackney, Anthony. Testosterone and Reproductive Dysfunction in Endurance-Trained Men. Encyclopedia of Sports Medicine and Science. Internet Society for Sport Science. 20 Sept 1998. http://www.sportsci.org/encyc/testosterone/testosterone.html.