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Exercise Heart Rate Question

Hi there.  I'm 34, a few extra pounds, and I've really been working out to improve my health and hopefully lose some weight.  I'm using primarily an incline trainer (treadmill with higher incline capability) and had a question about heart rate.

I know the most common formula for max heart rate (MHR) is 220-34(age)=186 bpm.  I try to target my HR between 93 (50% max) and 158 (85% max).  However, I'm working with incline trainer programs to build endurance, and at this point they sometimes briefly cause me to exceed the 158 number and approach 186 (100% of max).  Generally these are ~30 minute programs with less than a third of it above 85% and only a few minutes near the actual MHR.

My primary question is:
- How dangerous is it to hit MHR if you feel fine?  Obviously I'm tired when the workouts get intense, but normal tired, and I feel like I want to keep progressing to more difficult workouts, but given my dad died of heart attack early, I want to be sure I'm safe.  I'd been making things easier when I'm within 10 beats of MHR, but I feel like I could keep going.  I suspect, since MHR varies, mine might actually be higher than the estimates, but it's hard to say.  As long as I don't go over MHR for long, is it safe to approach/hit it?  Or should I stick to the 50-85% of MHR?

6 Responses
Avatar universal
First have you spoken to your doctor about exercising? If you have any medical conditions or are on medication then it could be a problem! You must first get the OK from your doctor!!
Going above 85% of your max. leads to poor heart-rate recovery, meaning it takes longer for heart rates to return to normal as per a 2002 study published in the "Canadian Medical Association Journal." Heart-rate recovery is a measure of cardiovascular fitness. The study also found increased incidence of non-sustained ventricular tachycardia and ST-segment depression among people exceeding the 85 percent recommendation, both of which are indicators of increased risk for cardiac mortality.
If you don’t have coronary artery disease or risk factors for a heart attack, it is possible to go over your recommended heart rate without injury.
Talk to your doctor!!
That being said try the following routine.

The Peak 8 routine it will quickly raise your heart rate 8 times for very short bursts, with a cooling down period in between. Ideally you’ll be sprinting or cycling full throttle for 30 seconds with a 90 second cool down in between each outburst.

This is the fastest way to lose fat and build muscle in the body. Peak 8 actually stimulates the growth hormone in the body. I encourage you to visit Dr Mercola’s site to learn more about Peak 8 fitness because I personally feel that it is one of the best ways to exercise, especially considering the speed at which you can lose fat and build muscle.

I highly recommend you read this article and watch the videos on the page. It will give you all the information you need to know about Peak 8 – Flood Your Body With This “Youth Hormone” In Just 20 Minutes

What you eat after Peak 8 training does matter

It’s recommended that you do not eat sugar or carbohydrate for 2 hours after the Peak 8 exercise because these foods can impact the release of the growth hormone in the body. The links are http://www.youtube.com/watch?v=zy7j9FRiJpg&list=PL9FxWnfq1Oyo9pHHUPHeQne4iqoZ4zTN_



Figure your heart rate by this formula
The Karvonen Formula is a mathematical formula that helps you determine your target heart rate zone. The formula involves using your maximum heart rate (MHR) minus your age to come up with a target heart rate range (which is a percentage of your MHR). Staying within this range will help you work most effectively during your cardio workouts.

an example of the Karvonen formula for a 23 year old person with a resting heart rate of 65 beats per minute (*to get your resting heart rate, take your pulse for one full minute when you first wake up in the morning or after you've resting for a while). This formula also includes an updated calculation of maximum heart rate (the previous formula was 220 - age, which has now been shown to be inaccurate):

206.9 - (0.67 x 23 (age)) = 191
191 - 65 (resting heart rate) = 126
126 * 65% (low end of heart rate zone) OR 85% (high end) = 82 OR 107
82 + 65 (resting heart rate) = 147
107 + 65 (rhr) = 172
The target heart rate zone for this person would be 147 to 172

First thing in the morning before you get out of bed have a clock with a second hand and check your resting heart rate then figure your rate by the
Karvonen Formula above.

You burn 30 percent more fat from doing cardio after a weights session as opposed to cardio on its own.
Avatar universal
Hi gymdandee, and thanks so much for the DETAILED reply!

Yes, I am cleared to exercise by my doctor!  No big medical conditions - I was getting borderline high with blood pressure, but have managed to get that down with some lifestyle changes (including exercise) and supplements to a very healthy level.  Also, I've actually been exercising regularly for some time (over a year regularly, and was on and off before that) - it's just I've increased the intensity a bit lately.  

Sprint 8 looks interesting.  My incline trainer doesn't support it natively, but the programs I'm doing aren't THAT different (they're Jillian Michaels designed workouts).  They definitely tend to have intervals tougher and then easier (with warmup and cooldown), but each one is different.  

Thanks for the alternative formulas as well!

I guess the main thing I'm confused on is, I've heard the going above 85% and poor heart rate recovery times before...but I'm unclear if that's a bad thing long-term, or if training at that intensity might eventually bring down heart rates.  
Avatar universal
It’s not a good idea because you're likely to suffer sore joints and muscles if you do. It raises your risk for a muscle skeletal injury. Above 85 percent of your maximum heart rate also puts you at risk for over training. When you over train, your body get weaker instead of stronger, which leads to increased fatigue and decreased performance. You also are more prone to injury.
Talk to your doctor and get his/her opinion!!
Avatar universal
Thanks gymdandee!

I'm curious now - how does an increase in heart rate increase risk of musculoskeleton injury?  I've read this before, but never quite understood the why behind it.

Will do re the doctor - thanks much!  I think I did overtrain once (but I was doing it every day...something I don't do anymore and make sure I have break days).  

Really appreciate all your help!
Avatar universal
The risk of musculoskeletal injury increases with the amount of intense physical activity. People who are normally inactive should start slow and gradually increase the intensity and duration of their participation in sports.
It increases your risk of injury during exercise and suppress your immune system. Exercise becomes excessive when the intensity, duration or frequency of your workouts interfere with adequate rest and recovery between workouts. Your fitness level dictates how much exercise is too much.
Over-training influences hormone secretion. Endurance athletes, who often perform hours of cardio each day, can experience increased secretion of cortisol -- a hormone associated with stress and weight gain. Additionally, over-training can suppress your appetite by increasing the secretion of two hormones known as epinephrine and norepinephrine. Inadequate caloric intake during difficult training programs can reduce your recovery rate and intensify over-training symptoms.
Too much exercise can suppress your immune system. As your body struggles with fatigue and inadequate muscle recovery, energy reserved for proper immune-system function redirects to repair overworked muscles and bones. Reoccurring illness during a workout program indicates a lack of rest and possible over-training. Additionally, training while sick can lengthen your recovery time and hinder your training to a greater extent than taking a few days off from exercise.
An elevated resting heart rate indicates over-training. For example, sustaining a resting heart rate of 80 beats per minute when your usual resting heart rate equals 65 beats per minute represents an elevated resting heart rate. In addition, exercising too much can increase the time it takes for your heart rate to return to a resting rate after a bout of exercise. Therefore, you should record your resting heart rate throughout your program and take notice if your resting heart rate increases over time.

Your musculoskeletal system comprises muscle and bone. Muscles and bones experience microscopic damage during exercise and require 24 to 48 hours of rest between workouts for adequate recovery. Frequently forgoing adequate rest periods reduces your strength and causes previously easy exercises to become difficult. Attempting exercise in a weakened state can lead to sprains or muscle tears.

Your likelihood of developing over-training symptoms depends on your exercise program and fitness level. Elite athletes who follow proper rest protocols can perform two workouts per day without negative results. On the other hand, an exercise beginner may show signs of burnout after training once a day for an entire month. You should begin a workout program with one or two weekly sessions and increase frequency as you become accustomed to regular exercise. Consult a doctor if you feel you are experiencing symptoms of over-training.

Source: Melissa Ross  American Council on Exercise
Avatar universal
Thanks gymdandee for all the fantastic information!  Very helpful!
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