Is there an 'optimum' running time for weight loss?

Question

Have just started running on a treadmill (working up to going outside!) every other night, and managing an hour at heart rate 155. I am pretty knackered by 40 mins, and wondered if I am actually doing myself any favours....maybe 40 mins is enough for weight loss?

What do you think?

Answer 1

I'm not a fitness expert but my fella is and he always says you should work out at a pace where you can still talk easily, as if you're out of breath your body doesn't burn fat as effectively. So probably 40 minutes on the treadmill at a nice pace every other night will be perfect... do lots of stretching as well as the fat burning!!

Answer 2

It all depends on your resting heart rate, but 155 sounds a bit too high for weight loss. Ironically, your heart rate needs to be slower than that in order to actually burn fat. Your current rate is the optimum rate for getting fit, not for losing weight.

Try slowing it down a bit to maybe about 125 bpm, or even better, go on the Orbitrech/Cross Trainer - they are much more effective for burning fat.

Answer 3

....

Your basic question is, is 40 minutes of running enough for weight loss?

No.  At 40 minutes, you are just entering the work out time zone when your body switches from producing energy by consuming sugars stored in your bloodstream to fat stored on your body.

40 minutes is tremendous cardiovascular exercise and great for improving your health.  But going beyond 40 minutes is good for losing fat.

Let's make one assumption:  You are eating fewer calories than you are consuming through your normal day's activities and running.

If your normal day's activities require 2,000 calories (a common benchmark), and if you run 40 minutes, you will be consuming about 2,400 calories per day.  So you need to eat less than 2,400 calories to begin to lose weight.

Okay, this indicates that you lose weight whenever you consume (eat) fewer calories than you consume (burn).  And this does happen.  However, the weight loss is minimal because your body begins metabolizing more efficiently when you are consuming just a bit fewer calories.

The point is, to lose (fat) weight, you need to burn it.  Going beyond 40 minutes will do that.

Something else comes into play:  "set point."  This is a weight that your body naturally and easily "bounces back to."

For example, let's say on average over a month you weigh 172 pounds, plus or minus 3 to 4.  If you lose 4 pounds, getting down to 168, you'll find your body craving more calories.  Most often, you'll give in to this.

If you gain 4 pounds, getting up to 176, you'll find that if you slightly increase your exercise and/or reduce your food intake, you'll fairly easily return to 172.

The trick is, re-setting the set point.

I recommend the following, for prolonged weight loss.

First (I am not original with this quote) think, "Eat food.  Not too much.  Mostly plants."

Second, alternate long and short workout days.  60 minutes, three times a week.  30 minutes four times a week.  Be sure to eat a bit lighter on the days you run 30 minutes.  (Frankly, extending workouts once to three times a week to 90+ minutes is most helpful.)

Third, if you really want to re-set your set point, realize you'll have to cut back on what you eat for at least three straight weeks.  It could be a bit miserable during that time.  However, by the end of three weeks, you will have lost 5-10 pounds, and gotten to a new weight that your average weight will 'revolve around'.

***A few comments about other answers***

You didn't say your age.  A heart rate of 155 for my 22 year old daughter indicates that she is just at a mild to moderate activity threshold.  A heart rate of 155 for me, a 54 year old old guy, is approaching my anaerobic threshold.  The point is, you've got to take heart rate in tandem with other pieces of information to determine "what it means."

Fat burning vs. cardiovascular fitness.  When you listen to some, it sounds like you burn fat at lower speeds or intensity of effort, and gain cardiovascular fitness (volume of blood per heart beat, essentially) by higher levels of intensity.  This is true.  However, going to higher levels of intensity does not prevent fat burning - that continues, and even accelerates.  It's just that at the lower levels of intensity, you won't achieve cardiovascular fitness as quickly.

***

I hope this is clear to you!

Regards,

Running_Dad