I've noticed a lower resting heart rate the morning after an extra strenuous weight training routine, but I've never made any measurements to show that it wasn't a quirk. I've never checked after a bike. So I just did a Google search out of curiosity.
Hardly anything out there with Google Scholar. The only one I could find was:
http://journals.lww.com/acsm-msse/Ab..._effect.9.aspx
Endurance exercise training has a minimal effect on resting heart rate: the HERITAGE study
WILMORE, JACK H.; STANFORTH, PHILIP R.; GAGNON, JACQUES; LEON, ARTHUR S.; RAO, D. C.; SKINNER, JAMES S.; BOUCHARD, CLAUDE
Abstract
This study determined the effects of a 20-wk endurance training program(The HERITAGE Family Study) on resting heart rate (HRrest). HRrest was obtained on a sample of 26 men and 21 women during sleep; during resting metabolic rate and resting blood pressure measurement periods in the early morning following a 12-h fast and 24-h post-exercise; and at rest prior to a maximal bout of exercise. Following training, the subjects exhibited a 16.0 ± 9.4% (mean ± SD) increase in˙VO2max (P < 0.05), but the HRrest for each of the resting conditions was decreased by only 1.9 to 3.4 bpm (P < 0.05), or an average across the three conditions of 2.7 bpm. In a larger sample of 253 HERITAGE subjects, HRrest obtained only at the time of the resting blood pressure measurement decreased by only 2.6 bpm, while˙VO2max increased 17.7 ± 10.0%. It is concluded that there is a significant, but small, decrease in resting heart rate as a result of 20 wk of moderate- to high-intensity endurance training; which suggests a minimal alteration in either, or both, intrinsic heart rate and autonomic control of HRrest.
But in the popular literature or regular Google, you get a lot of hits. Here's one:
http://en.wikipedia.org/wiki/Heart_rate
"Resting heart rate (HRrest) is a person's heart rate when they are at rest: awake but lying down, and not having immediately exerted themselves. Typical healthy resting heart rate in adults is 60–80 bpm,[8] with rates below 60 bpm referred to as bradycardia and rates above 100 bpm referred to as tachycardia. Note however that conditioned athletes often have resting heart rates below 60 bpm. Tour de France cyclist Lance Armstrong has a resting HR around 32 bpm, and it is not unusual for people doing regular exercise to get below 50 bpm."
I think it's so commonly known the resting HR does respond to exercise that nobody studies it. I doubt Armstrong was born with a 32 RHR. On the other hand, his heart volume is in the top 99% or there abouts according to tests at the Cooper clinic.
Then too, I doubt atheletes would still be using the Kavonon concept to define their HR zones if resting HR was not responsive to fitness. My understanding is that you recalulate your Zones every few months to accomodate the change in RHR as one's fitness improves. Maybe not.
I might add that there is a logical rational for a decrease in RHR. Based on my reading, heart volume per stroke increases with training. More blood/beat should mean fewer beats required to fuel a resting body.
Maybe I need a night in a Holiday Inn Express.
Al