Thursday, August 23, 2012
Is 30 Minutes of Exercise Better Than An Hour?
An article claiming less is more when it comes to weight loss and exercise hit the wires today. And while it’s decent if you read the entire thing it requires some explanation because the title is misleading. The details as to why are mainly left out, which come down to two physiological factors that I’ll go into today.
30 minutes exercise 'better than an hour of training' for weight loss
It’s important to first note that it’s not saying less exercise is better for weight loss for everyone. The title indicates this but the article shows it’s only better for the study’s demographic, which was both over weight and out of shape. So let’s look at why.
1. The first ten minutes of exercise is the key for most of us. This has been known for a long while but it’s been getting a ton of play lately. A recent study showed that 10 minutes of exercise can be better than an hour if it’s constructed correctly.
These 10 min studies highlight the importance of high intensity work and its effect on hormonal changes. While this study did not going into such depth, all exercise burns more calories in the first few minutes than when you settle in, no matter what you do. This means that you get the effect of high intensity training for a few minutes even when you aren’t exercising hard. This is because you burn muscle glycogen when you begin exercising until your body is warmed up. Once warm, your body starts to conserve; using fat stores for low intensity movements and saving glycogen for high intensity outputs.
A strong hormonal response (triggered by glycogen-sucking anaerobic work) is what you want in order to make the quickest adaptations to your body. You always get one at the beginning of a workout but it's harder to induce them once you’re warm and moving easily. However, high-level athletic training reverses this so the most important period becomes the push you make towards the end of the workout when you are tired, which can create an even greater hormonal response provided that you are fit enough to handle the workload. So, while short exercise is better than longer exercise by some measurements, there are also times, especially in conditioned populations, where the end of longer exercise is what matters most.
2. Exercise is only as effective as your ability to recover from it. Hence the cliché that you only get stronger at rest. If you overtax your body more than you can recover from you get worse before you get better. This is more than anything else the key to this study. By choosing a deconditioned population they were ensuring success because over the course of the study those doing more exercise became overtrained and had to recover from that state before they probably saw a lot of weight loss.
What this study doesn’t tell us is that if you lengthened it, at some point, those doing the longer workouts would outpace those doing the shorter ones. The laws of progressive overload mean that continual stress must be placed on the body in order to keep fitness progression moving forward. This is why if you run 5 miles everyday it will have less an effect as you get fitter. 30 minutes isn’t better than 60 for everybody, but it certainly is better for some. But in fitness is a moving target. As you get more fit you require more stress in order to continue to get fitter. This is why P90X is harder and longer than Power 90.
any excuse to post the 'torture test' works for me.
I’ve written on this subject before from many angles, such as how to choose the right exercise program , but important to address it from many sides. We don’t all need to be able to do Insanity in order to look great and call ourselves fit. For some of us Hip Hop Abs would be the better choice. Less can indeed be more. The only constant is that the human body needs exercise to function properly and some is almost always better than none.
Special thanks to Denis over at the Fitness Nerd for inspiring this post.