Here’s a new study from our lab entitled “Self-recorded heart rate variability profiles are associated with health and lifestyle markers in young adults”. The full text can be accessed for free through this link: https://rdcu.be/cUd9T. A practical summary is provided below. We’ve been tracking ANS status in athletes via daily ultra-short HRV for nearly 10 years now. In general, we (and others) have found that higher and more stable values are often observed in athletes who are more aerobically fit and who are adapting well to training. Contrastingly, lower and less stable values are commonly ..read more

Here’s a quick look at our latest study examining cardiac-autonomic responses to preseason camp in the heat among college football players. The free full text can be accessed here: Heart rate variability in college football players throughout preseason camp in the heat IJSM.  Intensive training periods tend to increase RHR and decrease HRV, reflecting stress and fatigue. However, adaptations to heat exposure (e.g., plasma volume expansion) tend to have the opposite effects. So we wanted to see what happens when players were exposed to both intense training and intense heat stress during p ..read more

Many of us have learned the hard way to stop training when we’re sick, and to ease back into it as we recover. In 2012, I contracted the hand/foot/mouth (HFMD) virus from my nephews. It was awful. After symptoms resolved, my training resumed with a deload week. Taking it easy, it took ~9 days after symptoms cleared for my 7-day rolling HR and LnRMSSD averages to return to within 1 standard deviation (SD) of pre-infection values (14-d baseline) (Fig. 1). These HRV values were obtained in the standing position after waking. Fig 1. RMSSD and HR responses to HFMD virus. I’ve observed the same gene ..read more

If success leaves clues, then there was something to learn from what Dan Howells & staff did to prepare GB 7s for the 2016 Olympics where they advanced to the gold medal final with an undefeated record. After sorting through the data (HRV, wellness, training load) and having several video and email conversations with Dan, we decided to share the story of their Olympic expedition. Prior to analyzing the data or obtaining specific details from Dan, I anticipated substantial decrements in status markers in response to a full day in transit (travel fatigue/jet lag, etc.), pre-tournament (arous ..read more

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 ..read more

Some questions I aimed to address in analyzing >10 years of daily HRV: Is it possible to substantially increase HRV for an extended period of time (>1 year)? Can a reasonably healthy individual make long-term increases in HRV through aging? (limited to 10 years in my case) Are changes in self-recorded HRV associated with changes in other health markers? What are some likely factors that contributed to changes in HRV and health markers? Brief Intro People with lower HRV are more likely to die of any cause than people with higher HRV.  In addition, nearly every known risk factor for ..read more

As part of my PhD work at Alabama, we tracked HRV in football players from day 1 of preseason training through to the national championship. A practical summary of some key findings follow the full-text link below. Season-Long Heart-Rate Variability Tracking Reveals Autonomic Imbalance in American College Football PlayersDownload Fluctuations in HRV are expected throughout a season. However, chronically suppressed values are cause for concern. Sustained parasympathetic hypoactivity is associated with various pathological conditions and is a hallmark of stress and impaired recovery in athletes ..read more

Short summary of and full-text access to a new study from our lab. Link to Full Text: Cardiac-Autonomic and Hemodynamic Responses to a Hypertonic, Sugar-sweertened Sports Beverage in Physically Active MenDownload Context: we previously resorted to standardized HRV measures performed in the athletic training room with college football players to overcome non-compliance with post-waking tests. Problem: pre-training hydration practices confound HRV measures. Players typically opt for cold bottles of water or Gatorade. Thus, we needed to determine how much and for how long these drinks impacted H ..read more

Here’s a new paper from my time at Bama. A practical summary follows the link and abstract below. Link to free full text: Effect of Competitive Status and Experience on Heart Rate Variability Profiles in Collegiate Sprint-SwimmersDownload Context: When first getting started with tracking HRV in athletes, the inter-individual variation in trend characteristics can be confusing. Some athletes will display very high values and others will show lower values. Likewise, some will show quite stable values while others display substantial day-to-day variation. Naturally, the following question arises ..read more

Our new meta-analysis determined that parasympathetic hyperactivity in overreached endurance athletes is best detected using weekly averaged versus isolated HRV values and in the standing versus supine position. Thanks to Agustín Manresa-Rocamora, Antonio Casanova-Lizón, Juan A. Ballester-Ferrer, José M. Sarabia, Francisco J. Vera-Garcia, and Manuel Moya-Ramón for inviting my collaboration. The full text can be accessed at the link below: https://onlinelibrary.wiley.com/share/author/WRPUS2WUBDYBTUBBUGQK?target=10.1111/sms.13932 ..read more