Update on changes in arterial stiffness and HRV

Here’s an October 2021 update on my quest to reduce arterial stiffness. For the original story and context, see previous post here.

After a year of >15 000 steps/day, continued adherence to improved nutrition, and a modified training approach, I saw another nice reduction in carotid-femoral pulse wave velocity (cf-PWV) along with an increase in RMSSD (see figure below).

RMSSD values (post-waking, standing position) from this October were the highest I’ve recorded to date. It seems that the more I try to reduce cf-PWV and improve my cardiovascular health, the more my HRV increases, despite no change in RHR. This strengthens my view that HRV can be an effective behavior-modification tool for health.

An important training modification that I implemented this October was changing my 10-min post-lift steady state air bike ride to intervals. The protocol is simply to pedal hard (though sub-maximally) for the first 10 s of every min for 10 min (excluding the first minute). Over ~4 weeks my “sprint” intensity naturally increased from ~450-500 to ~500-550 watts and recovery intensity from ~150 to ~180 watts. I’m pretty confident that this change accounts for the further increase in RMSSD. I performed a very similar protocol back in 2014 (post-lift intervals, 2014 figure re-posted below) for 2 weeks and saw an immediate increase and stabilization in my RMSSD values (middle of trend, LnRMSSDx20), which reverted to “normal” after cessation. My October 2021 PWV assessment occurred 2 weeks after starting this protocol, so it’s hard to say how much this may have had an effect.

daily trend aerobic weeks

Post-RT interval training may be a more time-efficient method to counteract the intense RT-induced arterial stiffening. Studies have shown that 30 min steady state, or 10 min of intervals on a bike attenuate post-RT increases in cf-PWV. Only 10 min of steady state riding attenuates RT-induced endothelial dysfunction (which is what originally inspired me to include this after my lifts). In terms of practicality, most lifters will unlikely perform 30 min of aerobic work post-RT. Ten min may be an easier sell. The intervals I’ve been experimenting with may be intense enough to provoke the desired effects, though short and submaximal enough for long-term use. Spearheaded by my incredibly intelligent and competent GA, Joe Vondrasek, we plan to investigate this further next year. We need to determine how such a protocol impacts both cardiovascular health markers and RT adaptations (i.e., day-to-day recovery, interference effect, etc).

I’m happy with the progress I’ve made thus far in reducing arterial stiffness (8.6 to 7.2 m/s). For context, below are norms for cf-PWV from this study. My values are now much closer to norms for my age group. Moving forward, my goal is to resume heavier powerlifting training while maintaining step-count, post-lift interval training, and aerobic work on non-lifting days to see if I can keep PWV under control while building my strength back up to respectable levels.

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