Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Exersize and heart rate

  1. Aug 24, 2003 #1
    Exercise and heart rate

    After reading a thread about overweight Americans I got to wondering about something; how does your heart rate factor into increasing your metabolism during exercise?

    Does the metabolic rate of your body cause you to actually lose weight or only cause you to lose weight faster providing you do not consume more calories than you burn?

    Perhaps this thread could get turned into something useful and members could post weight loss tips & techniques.

    How do you increase your body’s metabolic rate, and what’s so great about having it increased, other than for calorie burning? Is it done by shear torture of prolonged maximum physical exertion, or simply by taking the value of your 'at rest' heart rate, then raising and holding your heart rate at a higher value through exercise over a long enough period of time (30 minutes?). Does this cause your metabolic rate to increase and remain elevated, for several hours afterwards, thus helping you to shed weight even as you sleep?
    How do you know what your heart rate is suppose to be?
    Is it;
    (220 – your age)(0.4) = minimum level
    (220 – your age)(0.6) = maximum level

    I'll check back after I finish my triple-ground gristle burger.
    Last edited by a moderator: Aug 24, 2003
  2. jcsd
  3. Aug 25, 2003 #2
    There are two main keys to losing weight:

    1) watching what you eat -- this is important for many things, not just weight loss. Get plenty of fruits and vegetables, drink tons of water, cut back on fatty foods, etc, etc, etc. Basically, the stuff your doctor and mother have been telling you for years :wink: . Of course, to lose weight, you generally will want to decrease you calorie intake. Don't try and cut back from only one area, like fats or carbs; just a general decrease overall (while still maintaining a healthy diet).

    Now, there are some things to remember about cutting calories. FIrst, your body has a certain daily requirement of calories. It needs these to maintain muscle, repair wounds, etc, and this is called your base metabolic rate (this is the number of calories you burn each and every day, regardless of your activity level). If you intake less than your BMR, then your body needs to get the energy elsewhere -- in other words, from your fat reserves. Intake more, and you will probably gain weight (in the absense of any physical activity).

    The key is to not cut back too much. Starving yourself is the worst thing you can do. When you deny your body the calories it needs to live, it will go into starvation mode in an effort to conserve whatever it can. When this happens, your body is more likely to burn off muscle instead of fat, which is bad. As well, your metabolism drops severely, which is also not good.

    Now, even if you cut back a reasonable amount (say 20%) your body still likes to make things difficult. A sustained drop in caloric intake will make your body lower its metabolic rate to match. So, even though you may lose weight initially, your body will eventually compensate. This makes it very hard to lose weight. It also makes it easier to gain weight. If you happen to splurge a couple of days and eat excess calories, your bodies metabolism is slower, and you are likely to retain it. To compensate for this, we go to point 2.

    2) exercise -- it's hard to do sometimes, but crucial to overall health and weight loss. Regular exercise will boost your heart rate, lung capacity, and your metabolism, leading to an increase in your BMR and more calories burned per day. As well, your metabolism will elevate during exervise, and stay elevated for a period afterwards, sometimes hours (depending on the length of your cardio session).

    The type of cardio you do really doesn't matter. Some activities burn more calories than others of course, but even walking for half an hour a day can have major benefits. If your main goal is to lose weight, you should keep the intensity low to moderate, and do the activity for longer. For eg., do an hour long walk at a slow pace instead of an all out run for 15 min. Your body burns calories (and fat) more efficiently at lower intensities.

    Weightlifting is also very helpful. First, the act itself burns a decent # of calories. As well, muscle is active tissue, meaning it burns calories throughout the day (as opposed to fat, which more or less sits there). Each pound of muscle you put on will burn some number of additional calories per day (I don't remember the number), which will increase your BMR. And of course, muscle looks a hell of a lot better than fat :wink: .

    Another thing to do is drink lots and lots of water. Your body uses water for just about every function it performs, so this a good idea anyway. For weight loss, it is also key. As I recall, it has to do mostly with your liver, which is responsible for metabolising fat. If you are dehydrated, your kidneys (which need lots of water) cannot function at peak efficiency, and they will recruit the liver to help out, taking it away from burning away that unsightly fat.

    Ultimately, remember that trying to do too much too quickly is usually self-defeating. People who lose a lot of weight in a short amount of time (usually using shady methods) are far more likely to gain it back. Slow, sustained weight loss through healthy eating and regular exercise is the way to go.
  4. Aug 25, 2003 #3
    I don't think heart rate and metabolism are linked. I think it has more to do with exersize pushing your body to become more efficient in turning fat and sugar into energy. You only have to elevate your heart rate slightly to lose fat, and actually...
    ...pushing your heart rate up too high actually minimizes fat burning! To metabolize fat, your body needs lots of oxygen. Past a certain point, your heart rate and breathing cannot keep you in an aerobic state, at which point your muscles go to an anaerobic energy-producing cycle which burns nothing but sugar.
  5. Aug 25, 2003 #4
    Re: Exercise and heart rate

    This is incorrect. As for a 20 year old, the maximum would only be 120. I know someone who did over 200 once. Similarly the minimum would be 80. There are many people who have resting heart rates at 50 area. Also, I would have thought that the resting heart rate increases with age.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Exersize and heart rate
  1. The Heart of Reality (Replies: 67)

  2. Heart failure (Replies: 26)

  3. Head And Heart (Replies: 2)