2024 – Oak Island Half Marathon

A fun start to the 2024 season in Oak Island. I decided to do a Half Marathon to try and accomplish a one of my goals of breaking 1:20 over the 13.1 miles. This didn’t happen today, but it was fun trying 🙂

3rd Place Overall, 2nd Place Overall Male.

Is Hypoxanthine the future for monitoring endurance performance?

Super interesting article on the use of Hypoxanthine (from sweat) being used as a predictor of performance in athletes.

Having done HR tracking, Power and over the last couple of years, Lactate, it’s always interesting to hear of new methods and advancements in performance, and opportunities to improve metabolic health. So while I am still waiting for a reasonable/practical real-time Lactate monitoring solution, maybe I should skip to the next big thing …

Check it out here: https://pubmed.ncbi.nlm.nih.gov/23670363/

Abstract

Purine metabolism reflects the exercise-induced muscle adaptations and training status. This study evaluated the utility of plasma hypoxanthine in the prediction of actual sport performance. We studied male athletes: 28 triathletes (21.4±2.9 years), 12 long-distance runners (23.2±1.9 years), 13 middle-distance runners (22.9±1.8 years) and 18 sprinters (22.0±2.7 years). Season-best race times were considered, achieved over standard triathlon, 5 000 m, 1 500 m and 100 m, respectively. Incremental treadmill test was administered to determine maximum and “threshold” oxygen uptake. Resting and post-exercise plasma concentrations of hypoxanthine, xanthine, uric acid and lactate were measured as well as resting erythrocyte hypoxanthine-guanine phosphoribosyltransferase activity. Simple and multiple regression analyses were used to identify significant contributors to the variance in performance. Hypoxanthine considered alone explained more variance in triathletes, long-distance runners, middle-distance runners and sprinters (r 2=0.81, 0.81, 0.88 and 0.78, respectively) than models based on aerobic capacity and lactate (R 2=0.51, 0.37, 0.59 and 0.31, respectively). Combining purine metabolites and cardiorespiratory variables resulted in the best prediction (R 2=0.86, 0.93, 0.93 and 0.91; r=0.93, 0.96, 0.96 and 0.95, respectively). In summary, hypoxanthine is a strong predictor of performance in highly trained athletes and its prediction ability is very high regardless of sport specialization, spanning the continuum from speed-power to endurance disciplines. read more

hDrop – Wearable Hydration Monitor

I *just* received my order of the hDrop gen 2 wearable hydration monitor, and used it for a short 45 min easy Zone 2 run. Based on my interest of sweat analysis, I was curious to compare my results to other tests I have done in the past. I plan to continue to use it for more sessions, and it will be interesting to see how the results fluctuate with the seasons.

MetricPrevious ValuePer hDropNotes
Avg Sweat Rate37Oz/h16.4Oz/hMy previous values were cycling, temps were relatively cool
Avg Sodium Concentration716mg/L – 1023mg/L901.1mg/LRange of 5 tests, last 3 were all at 1000mg/L +- 50.

After my first quick and dirty test, the unit is probably quite accurate on the sodium concentration, but I am unsure about the sweat rate. My past sweat tests were done based on weight loss during the exercise, cycling (not running) and majority were indoors. Based on the effort and ambient temp, I think around a 500ml sweat loss seems correct. read more

Endurance Racing – Sweat Loss

As one of the three important Fuel and Hydration, sweat loss, and more specifically, the replacement of fluids, is an incredibly important aspect of endurance racing, and is strongly correlated to race day survival, performance and recovery. The other two aspects, fuel (primarily carbohydrates) and electrolytes (primarily sodium) are the other two components. Without any one of the three, long distance and endurance events, or races, become considerably more challenging, and the chances of you finishing, drastically diminish.

Understanding how much fluid you have to consume during an event is determined by a variety of factors and variables. A few of the variables:

Time of Day, Heat, Humidity, Diet, and Effort. In addition, your sweat rate is unique and may also change throughout your life. Unlike your relative sodium concentration, which generally is constant throughout your life and in the majority of circumstances. read more

DIY: Endurance Fuel

Running Notes

LTHR

Zone 1: Less than 85% of LTHR – 136

Zone 2: 85–89% of LTHR – 136 – 143

Zone 3: 90–94% of LTHR – 144 – 150

Zone 4: 95–99% of LTHR – 151 – 158

Zone 5a: 100–102% of LTHR – 159 – 163

Zone 5b: 103–106% of LTHR – 163 – 170

Zone 5c: More than 106% of LTHR – 170+