Guest Post: Should You Do Cardio Before or After Eating?

 

This week’s Fitness Post is brought to you by personal trainer Igor Klibanov from Fitness Solutions Plus.

Should You Do Cardio Before or After Eating?

cardio_before_after_eatingThis is the most recent question asked to me by a subscriber. Seems like a simple question, with a simple answer, but I like to complicate things in order to create content for this newsletter. Just kidding. But let’s dive into it anyway.

First of all, we have to define “cardio.”

Traditionally, cardio is any form of physical activity that elevates the heart rate to a level high enough to have aerobic benefits. Typically, that’s 60-70% of your maximal heart rate (to figure out your maximal heart rate VERY roughly, subtract your age from 220. So if you’re 50 years old, your maximal heart rate is 170, and 60% of that is 102. 70% of that is 119. There are better ways of figuring out your maximal heart rate, but that’s beyond today’s newsletter).

To get your heart rate that high requires some moderate exertion. That’s either jogging, or walking quickly uphill. A brisk walk, or a slow walk won’t get you there, so it can’t really be considered “cardio”, because unless you’re really out of shape, the intensity is not sufficient to cross that 60-70% threshold.

So if the question is really “should you do cardio before or after eating?”, the answer is either immediately before, or at least 1.5-3 hours after (depending on the size and composition of the meal).

Having said that, there are very nice benefits to doing a light walk right after a meal. Light enough that it doesn’t have aerobic effects.

Why would we want to do that?

For one thing, it helps prevent your blood sugar from rising too high very quickly. When muscle contract, even gently, they use up blood sugar as fuel.

Also, if you ate a particularly big meal, the light walk can help with digestion.

On the other hand, walking before a meal does not have this blood sugar lowering effect, but higher intensity exercise indeed does.

So to the question of “should you do cardio before or after eating?”, the answer is “if doing high intensity activity, do it before or 1.5-3 hours after, or if doing low intensity activity, do it immediately after.”