In my last blog, we focused on how food can effect our metabolism, or the thermic effect of food (TEF). That makes up a very small percentage of the calories our bodies burn. Let’s talk about where a larger amount of calories are burned. This is key for anyone trying to lose weight.
Similar to TEF, the thermic effect of exercise is abbreviated as TEE. Any physical activity we do during our activities of daily living (dishes, washing our clothes, etc) will elevate our metabolic rate. Adding exercise on top of that, elevates it even more. How much does it elevate it? For the moderately active person, TEE amounts to about 15-30% of total caloric expenditure (how many calories were burned). For more active individuals like endurance athletes, TEE can account for 60% of our total caloric expenditure.
It turns out, certain sports produce a greater energy expenditure than others. Makes sense right? Cycling, swimming, rowing, running and body building rank higher than volleyball, handball, hockey and gymnastics. The first four of the highest ranking here are for the most part, endurance sports. The lower ranking are more likely team sports, where you are stopping and starting. Arguably the toughest endurance sport in the world, The Tour de France has a caloric breakdown like this:
- 22 days of riding covering over 4000km
- cyclists have a mean energy intake of around 5000+calories
- cyclists have a mean energy expenditure of around 6000+ calories
- the breakdown by macronutrients was 62% carb, 23% fat, 15% protein
- 50% of the total intake was taken on the bike (Saris et al 1989)
Even though the riders are taking in 5000 calories, they are always in an energy deficit. For most of us, even those of us that are considered crazy because we train 10-20 hours a week, this is a high caloric expenditure for one day.
So, how can we maximize our caloric expenditure, or how can we burn more calories in our training?
There are two main ways, polar opposites from each other.
- The first is longer, endurance training. And this training doesn’t have a very high rate of perceived exertion. It can be called intense, but just because the exercise is lasting for 60+ min (usually 90min). The intensity is only 60-80% of your Vo2 max, which corresponds to someones endurance or conversation pace.
- The second way is by doing shorter intervals at a high intensity, closer to 90% of Vo2 max. The other term for this type of exercise is HIIT (high intensity interval training). Examples of this include olympic lifting, tabata, cross fit and others.
Why do these two types of exercise, increase our caloric expenditure? Yes, both types of exercise burn calories while an athlete is doing the particular exercise or sport, but it’s what happens after the exercise is done, that really matters. This is called EPOC, or Excess Post Exercise Oxygen Consumption. EPOC was originally called oxygen debt. Or the amount of oxygen consumed above baseline after exercise. Now, researchers use it to describe several factors that relate to the body returning to homeostasis, where it wants to be. These include replenishing our energy resources, re-oxygenation of the blood, cooling our bodies to normal temperature and returning heart rate and ventilation back to baseline. The total difference in calories burned after exercises with great EPOC range from 51kcal to 127kcal (Haltom et al 1999, Burleson et al 1998). This might not seem like a lot, but over time, can add up. This can be 306-762 extra calories burned if someone is exercising 6x week. And one pound of fat equals 3500 kcal, so you could be looking at losing approximately 1 pound of fat every month just from EPOC.
The goal of anyone trying to lose weight, or be in an energy deficit, should try to either up their exercise to moderate intensity for prolonged periods of 60+ min, or do shorter, more intense interval training. Both will increase you EPOC, and you will be burning more calories for a longer time. In addition to increasing your EPOC for a short window after exercise, a study by Bahr, 1992, showed that either types of exercise listed above, will elicit higher oxygen consumptions for up to 12 hours post exercise. This is even including when the person was resting. In addition, some endurance athletes that do two a day workouts, will chronically have an elevated metabolic rate. Pretty nice to not have to do anything else for 10 hours and you are still burning more calories.
When we as athletes are trying to lose weight, we need to focus on what types of foods we are putting into our bodies, and what types of exercise we are doing. Both can have a big impact on our weight loss. So, I’ll be eating more protein, and when I can exercise again, I’ll be doing more long endurance exercise and short HIIT.