Sep 18, 2012

Resting Heart Rate, the key to long term health, fitness and endurance training success. 

Resting heart rate monitoring can be one indicator of long term heath
helping you detect that health change, like a rogue wave. 

Recently in Human Kinetics, this article reprint drove home some simple ways to monitor and detect early changes in your bodies health and level of fitness.

When I was in deep training for the English Channel my resting heart rate was 42-48 regularly. Now 6 months later, and just getting back into the training, weight lifting and a routine post cardiac stent placement in June for blockages we unexpectedly discovered early in the year my resting heart rate was 51 this morning. My experience tells me that you lose quickly the benefits of training and this will come back too. 

One of the most valu­able long-term pieces of infor­ma­tion you can gath­er is rest­ing heart rate. When you wake up each morn­ing, take a minute to get an accu­rate rest­ing heart rate and keep a log. You’ll find this an invalu­able tool, pro­vid­ing feed­back on injury, ill­ness, over­train­ing, stress, incom­plete recov­ery, and so on. It is also a very sim­ple gauge of improve­ments in fit­ness. We know ath­letes who have gath­ered rest­ing heart rate data for years and in a day or two can iden­ti­fy a 1 or 2 bpm ele­va­tion that pre­cedes an ill­ness or a bonk ses­sion. Some newer heart rate mon­i­tors have the capac­i­ty for 24-hour mon­i­tor­ing. 

Sev­er­al fac­tors affect heart rate at rest and dur­ing exer­cise. In gen­er­al, the main fac­tors affect­ing heart rate at rest are fit­ness and state of recov­ery. Gen­der also is sug­gest­ed to play a role, albeit incon­sis­tent­ly (more about this later). In gen­er­al, fit­ter peo­ple tend to have lower rest­ing heart rates. Some great ath­letes of the past have record­ed remark­ably low rest­ing heart rates. For exam­ple, Miguel Indurain, five-time win­ner of the Tour de France, report­ed a rest­ing heart rate of only 28 bpm. The rea­son for this is that, with appro­pri­ate train­ing, the heart mus­cle increas­es in both size and strength. The stronger heart moves more blood with each beat (this is called stroke vol­ume) and there­fore can do the same amount of work with fewer beats. As you get fit­ter, your rest­ing heart rate should get lower. 

The sec­ond main fac­tor affect­ing rest­ing heart rate is state of recov­ery. After exercise, par­tic­u­lar­ly after a long run or bike ride, sev­er­al things hap­pen in the body. Fuel sources are deplet­ed, tem­per­a­ture increas­es, and mus­cles are dam­aged. All of these fac­tors must be addressed and cor­rect­ed. The body has to work hard­er, and this increased work results in a high­er heart rate. Even though you might feel okay at rest, your body is work­ing hard­er to repair itself, and you’ll notice an ele­vat­ed heart rate. Mon­i­tor­ing your rest­ing heart rate and your exer­cise heart rate will allow you to make appro­pri­ate adjust­ments such as eat­ing more or tak­ing a day off when your rate is ele­vat­ed. 

These same fac­tors of recov­ery and injury also affect heart rate dur­ing exer­cise. The fac­tors that ele­vate rest­ing heart rate also ele­vate exer­cise heart rate. If you’re not fully recov­ered from a pre­vi­ous work­out, you might notice, for exam­ple, at your usual steady-state pace, an exer­cise heart rate that is 5 to 10 bpm high­er than nor­mal. This is usu­al­ly accom­pa­nied by a rapid­ly increas­ing heart rate through­out the exer­cise ses­sion. 

An extreme­ly impor­tant fac­tor affect­ing exer­cise heart rate is tem­per­a­ture. Warmer tem­per­a­tures cause the heart to beat faster and place con­sid­er­able strain on the body. Sim­ply put, when it is hot, the body must move more blood to the skin to cool it while also main­tain­ing blood flow to the mus­cles. The only way to do both of these things is to increase over­all blood flow, which means that the heart must beat faster. Depend­ing on how fit you are and how hot it is, this might mean a heart rate that is 20 to 40 bpm high­er than nor­mal. Fluid intake is very impor­tant under these con­di­tions. Sweat­ing changes blood vol­ume, which even­tu­al­ly can cause car­diac prob­lems. The sim­plest and most effec­tive inter­ven­tion to address high tem­per­a­ture and heart rate is reg­u­lar fluid intake. This helps to pre­serve the blood volume and pre­vent the heart from beat­ing faster and faster. 

Anoth­er impor­tant fac­tor affect­ing exer­cise heart rate is age. In gen­er­al, MHR will decline by about 1 beat per year start­ing at around 20 years old. Inter­est­ing­ly, resting heart rate is not affect­ed. This is why the basic pre­dic­tion equa­tion of 220 – age has an age cor­rec­tion fac­tor. As a side note, this decrease in MHR often is used to explain decreas­es in VO2max and endurance per­for­mance with increas­ing age, because the num­ber of times the heart beats in a minute affects how much blood is moved and avail­able to the mus­cles. We have coached and test­ed thou­sands of athletes, and the gen­er­al trend is that ath­letes of the same age who pro­duce high­er heart rates often have high­er fit­ness scores. How­ev­er, your MHR is what it is, and you can­not change it. Don’t obsess over it.

A final fac­tor is gen­der. Recent stud­ies have sug­gest­ed a vari­a­tion in MHR between males and females. How­ev­er, the data are incon­clu­sive with the cal­cu­la­tions resulting in lowerMHRs for males ver­sus females of the same age, while anec­do­tal reports sug­gest that theMHRs are actu­al­ly high­er in males. In gen­er­al, females have small­er hearts and small­er mus­cles over­all than males. Both of these fac­tors would sup­port the con­clu­sion of a high­er MHR in females, cer­tain­ly at the same work­load. We have to con­clude that the jury is still out on the gen­der effect.

This excerpt is from the author of Heart Rate Train­ing. It's pub­lished with per­mis­sion of Human Kinet­ics, Roy Benson.

No comments:

Post a Comment