Heartrate, Perceived Exertion, etc.
I am trying to improve my cardiovascular fitness, but would like some input regarding my activities. I understand that anything I'm told isn't medical advice and that only a qualified medical professional should be the resource I use to make decisions regarding my health. I simply want others' input for my own uses.
Current situation analysis:
* I am a 24 year-old male who, as of January 28, 2012, weighs about 250 pounds. Body fat was measured at 37.08% using the Jackson-Pollock 3-point caliper method. (obesity is >25%)
* I do not engage in strength training exercises, but do cardiovascular activities. Activities are limited to an inside environment (gym) and include a recumbent bike and treadmill. A typical "high intensity" day includes 30 minutes on the bike and 15 to 30 minutes on the treadmill afterwards. A "low intensity" day features light cardiovascular activity for about 20 to 30 minutes. Days are split up into blocks. Each block is a period of time of 30 minutes or less and may be high intensity or low intensity.
* For high intensity blocks, my strategy is as follows: Increase intensity to get the heartrate up to 150. Maintain the heartrate between 150 to 160. When the heartrate reaches 160, start a countdown; after three minutes, lower the intensity of the exercise until the heartrate drops back down to 150. After it has consistently stayed at the lower 150's for ten minutes, another attempt at increasing the intensity (per the previous rules) may be made.
* For low intensity/recovery blocks, my strategy is as follows: Maintain intensity to keep the heartrate at 65% of its maximum. (126 bpm) If the heartrate increases beyond this limit, lower the intensity of the activity.
* In 2008, a cardiologist diagnosed me with the following: hyperlipidemia, stage 2 hypertension, and "mild reversible inferior defect." Temporary limits were placed on weight-lifting, but were eventually lifted.
People tell me that I should listen to my body, but -- as past experience with sugar cravings and hypoglycemia have taught me -- often my body lies to me. Exertion and stress is to expected during any type of physical exercise, but it is hard for me to tell when I am overexerting myself. I feel relief when I lower the intensity of the exercise, but that seems to be a natural response to lowering the difficulty in all situations; of course the body's not going to "want" to keep the intensity going. I don't "enjoy" the feeling of stressing my muscles and being short of breath, but I would presume that this is a part of the essence of training: doing something stressful repeatedly until you adapt and it is no longer stressful.
It's strange because there are times (especally with caffeine consumption) when I get on that bike and feel like the only thing that could stop me is shortness of breath, and there are other times that I can get on and have a low heartrate, full breath and be totally recovered, but the leg muscles themselves become extremely sore quickly during the workout -- even after a day of rest or active recovery. There are times when doing cardio that I can actually feel my heart pounding within my chest like it's threatening to jump out! I usually experience this sensation when the heartrate rises to 155 or higher. Other than this, however, I do not feel pain (other than what I perceive to be soreness), experience headaches, or feel dizzy.
Strangely enough, consuming caffeinated beverages (like coffee, iced tea, and so on) seems to increase my "tolerance" to this stress. Although my heartrate may rise to high levels, I do not feel "stressed" and my muscles do not feel sore during the workout. I draw the line for heartrate levels at 160 bpm, though; since I am not on a treadmill under the direct supervision of a cardiologist, I see no need to give myself a stress test. The most I've allowed my heartrate to reach during a workout is 170. If it becomes that high, I'll immediately lower the intensity of the exercise considerably to give myself an opportunity to recover mid-exercise.
Being properly hydrated and cooled also seem to have an influence on my heartrate. If I am dehydrated, my heartrate rises and the sensation of fatigue comes more quickly. If I am sweating, having a fan blow air on me to cool me down seems to keep my heartrate under control. Otherwise, I will tire more quickly and my heartrate will rise.
When starting a workout, my heartrate may also take time to reach a certain level that reflects the intensity of my workout. After research, I have identified this phenomenon as "cardiac drift."
I've researched the benefits of high-intensity exercise and have had the opportunities to experience them first-hand in the past. After an intense cardio session, I would experience improved mood and sleep more easily. So, I don't want "moderate" exercise; I want intense exercise. Of course, obvious pain, headaches, and dizziness are red flags that I always look out for to stop a workout; nevertheless, I can't help but wonder if my heart is working too much. If I otherwise feel fine when doing the workout, do I need to worry about my heartrate? Will something bad happen if I leave it in the 160's or beyond for an extended period of time? I may fatigue my muscles, but that's actually the end result I want to help them build up for the exercises I am doing.
Also, what role does my weight play in this? As a result of obesity, all physical activities I do require considerably more effort from my muscles and heart. My cardiologist advised that weight-lifting raises blood pressure. I infer that any activity that raises blood pressure must have an even more profound effect on obese individuals because of the increased effort of the muscles. Should I simply focus on changes to my diet and moderate intensity exercise until my body fat percentage drops to an acceptable level (24% isn't lean, but I'll take it!!), or should I stay the course to try to reap the benefits now?
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