Al Kubeluis wrote: As
> you train, you will find that your max hr increases since your conditioning improves.
Existing studies in a review suggest that HRmax decrease with conditioning. I haven't read the full
article (or if I have I don't have it at my finger tips) but here's an abstract by author that Sam
pointed me to back in Sept under "Heart Rate Monitor Strategies". Note: I think people use the term
HRmax differently and I'm not sure how they define it in this article, but most likely involves some
testing protocol, hence HRmax may fluctuate a little based on training and type activity. I split
the most relevant sentence out of the abstract for easy viewing. There may be other more current
papers and possibly conflicting results.
> 1: Sports Med. 2000 Jan;29(1):13-26.
>
> Evidence and possible mechanisms of altered maximum heart rate with endurance training and
> tapering.
>
> Zavorsky GS.
>
> Department of Experimental Medicine, University of British Columbia, Vancouver, Canada.
>
[email protected]
>
> Exercise physiologists, coaches and athletes have traditionally used heart rate (HR) to monitor
> training intensity during exercise. While it is known that aerobic training decreases submaximal
> HR (HRsubmax) at a given absolute exercise workload, the general consensus is that maximum HR
> (HRmax) is relatively unaltered regardless of training status in a given population. It has not
> been seriously postulated as to whether HRmax can change modestly with aerobic
> training/detraining.
Despite several sources stating that HRmax is unaltered
> with training, several studies report that HRmax is reduced following regular aerobic exercise by
> sedentary adults and endurance athletes, and can increase upon cessation of aerobic exercise.
Furthermore, evidence suggests that
> tapering/detraining can increase HRmax. Therefore, it is plausible that some of the same
> mechanisms that affect both resting and HRsubmax may also play a role in altered HRmax. Some of
> the proposed mechanisms for changes in HRmax that may occur with aerobic training include
> autonomic (extrinsic) factors such as plasma volume expansion and(enhanced baroreflex function,
> while some nonautonomic (intrinsic) factors are alteration of the electrophysiology of the
> sinoatrial (SA) node and decreased beta-adrenergic receptor number and density. There is a high
> correlation between changes in both maximal oxygen uptake (VO2 max) and HRmax that occurs with
> training, tapering and detraining (r= -0.76: p < 0.0001; n = 314), which indicates that as VO2max
> improves with training, HRmax tends to decrease, and when detraining ensues, HRmax tends to
> increase. The overall effect of aerobic training and detraining on HRmax is moderate: effect sizes
> based on several studies were calculated to be -0.48 and +0.54, respectively. Therefore, analysis
> reveals that HRmax can be altered by 3 to 7% with aerobic training/detraining. However, because of
> a lack of research in the area of training on HRmax, the reader should remain speculative and
> allow for cautious interpretation until further, more thorough investigations are carried out as
> to the confirmation of mechanisms involved. Despite the limitations of using HR and HRmax as a
> guide to training intensity, the practical implications of monitoring changing HRmax are: (i)
> prescribed training intensities may be more precisely monitored; and (ii) prevention of
> overtraining may possibly be enhanced. As such, it may be sensible to monitor HRmax directly in
> athletes throughout the training year, perhaps at every macrocycle (3 to 6 weeks).
--
"Success is different things to different people" -Bernd Heinrich in Racing the Antelope
