will doing a short intense exercise be worse/not as good as doing a more moderate exercise for the same period of time

Question

I find myself getting fairly busy to where I don't really feel like I have time to work out. As a matter of fact, I really only get sporadic exercise. The other day I had a thought that I should be able to give myself at least 5 minutes. Obviously I'm a little out of shape so I won't be able to press myself super hard, but the thought that I had is that I could run around the neighborhood - and especially sprinting to really get the most out of the short time.

Is that thought correct, or will doing a short intense exercise be worse/not as good as doing a more moderate exercise for the same period of time?

My main goal is just to be generally more fit. It would be nice to increase my strength (which running isn't going to help a whole lot of course), but I definitely want to not get so tired when I do physical activity.

Answer 1

Think about what five minutes could possibly yield in conditioning. Obviously you have to issue a challenge to your heart and lungs walking isn't going to help you.

Suppose you did the opposite of walking. Suppose you did wind sprints for five minutes, that is, you ran 40 meters in one direction as fast as you can- a full out sprint every step of the way, then immediately turned around and did it again in the opposite direction.

What you would find is you couldn't do it for five minutes. In fact, no-one can because as hard as you can exercise is shorthand for anaerobic and no one's body can process the waste products of anaerobic exercise fast enough to keep the body working anaerobically for five minutes. The result is, you stop and your heart and lungs are working as hard as they can.

So now you have a formula for working out hard in five minutes. No doubt your conditioning will improve over what it is now, the thing is, it's not clear it would improve as much as if you were able to dedicate 20 minutes or hard exercise interspersed with lower intensity exercise. 20 minutes 3 times a week is the minimum of time usually cited as needed for progressive improvement of your heart and lung capacity and efficiency.

Under that assumption, repeated runs at achieving the impossible- a full 5 minutes of continuous wind sprints- would not be as effective for conditioning. That said, I am not aware of any researchers who have investigated the effects of a such specific and limited regime.

You can get in a completely challenging (to say the least) workout in five minutes. Whether it's a workout that will lead to progressively increased fitness and if so, what that fitness might yield in terms of capacity and endurance outside of doing wind sprints, I am not sure. I am not advising you to do this (consult your doctor), I am merely pointing out that 5 minutes is actually plenty of time to give your heart and lungs a real workout.

Something to think about.

Answer 2

down vote Your thought process is right. Doing high-intensity workouts will force your body into EPOC(Excessive Post-exercise Oxygen Consumption) where your body is burning fat even hours after your workout. There are many types of HIIT programs that you can follow. One of them is sprinting for a certain amount of time, let's say 20 seconds and slow jogging for 10 seconds. Repeat this for 5-10 times. For higher difficulties, you can increase the intervals or the number of times. If you want to stay indoors, you can experiment and create your workout routine with different combinations of sit-ups, burpees, jumping jacks, push-ups, squats,etc. The idea is to get your heart pounding and keeping it there for the whole workout.