Question: My max heart rate is usually right at 160 bpm. I did some heavy training for eight weeks (sprint intervals, hill intervals, long rides), then took six days off. No riding or other exercise. Now when I do sprint intervals, my max HR is about 10 beats higher than before my break. Is this caused by the layoff? — Lee D.
Coach Fred Matheny Replies: Yes. And your heart rate results tell us a lot about the importance of rest.
Your heart is a “follower” in the sense that it does what your muscles tell it to do. If you’re riding hard, the heart has to beat fast to supply the legs. If your legs are tired, they can’t “ask” the heart to work hard.
After weeks of tough interval training or other strenuous riding, your muscles are tired and probably chronically depleted of glycogen. So they can’t work hard enough to force your heart to higher levels. But if you give them a week to rest, recover and replenish, then they’ll push your heart to its real maximum.
The same is true of your lactate threshold heart rate. It will rise about 5% with significant rest. This will allow you to ride harder before reaching the point where heavy breathing switches to panting and you have to back off.
My teammates and I experienced a similar heart rate phenomenon during the 1996 Team Race Across America.
On the first day, we hit the heart rates we expected based on our training. But during the final four days, we couldn’t get our heart rates up within 10 or even 20 beats of those figures.
Even so, we were riding just as fast. We covered about the same number of miles (530) every 24 hours. Exercise physiologists aren’t sure why that can happen.
It’s probably not a problem to train when you can’t get your heart rate up IF you aren’t experiencing other overtraining symptoms.
Above all, your experience underscores the importance of rest before a big event.
Coach Fred Matheny is an RBR co-founder who has four decades of road cycling and coaching experience. He has written 14 eBooks and eArticles on cycling training, available in RBR’s eBookstore at Coach Fred Matheny, including the classic Complete Book of Road Bike Training, which includes 4 eBooks comprising 250 pages of timeless, detailed advice and training plans. The Complete Book is one of the many perks of an RBR Premium Membership. Click to read Fred’s full bio.