Uploaded January 2026 | Updated September 2026, 2 weeks ago
Dr. Pinkston and metabolic expert Jim LaValle explain why Heart Rate Variability (HRV) is the ultimate metric for stress and aging. Learn how to track your HRV, avoid the "caffeine trap," and use simple breathing and movement techniques to retrain your nervous system for a longer, healthier life.
Dr. Pinkston and metabolic expert Jim LaValle explain why Heart Rate Variability (HRV) is the ultimate metric for stress and aging. Learn how to track your HRV, avoid the "caffeine trap," and use simple breathing and movement techniques to retrain your nervous system for a longer, healthier life.

![Stop Over-Exercising! Protect Your Heart & Thyroid!
This video explains the benefits of interval training for heart conditioning, emphasizes the importance of combining cardio with resistance training, and discusses the potential negative effects of over-exercising on thyroid hormones and heart health.
[25:34-25:48]
Interval training involves alternating between high-intensity bursts and recovery periods to improve heart function.
for say one minute. 2 minutes walk, one minute there. And thats giving Whats that doing? Thats changing the way your heart is beating, right? Cause its beating harder, and now youre telling it to slow down. Then youre beating harder, telling it to slow down.
[25:48-26:08]
Resistance training is crucial for conditioning the heart, building muscle, and strengthening bones.
Yeah. Yeah. So youre conditioning that. And then Im always a fan, not so much for, you know, weight training for the sake of pure heart rate variability- Mm-hmm. but make sure youre getting some, make sure youre getting some resistance training- Mm-hmm. to go with that. Because, you know, we need our bones and we need our muscle. And you and I are both big fans of resistance training.
[26:08-26:26]
Combining cardio and resistance training is essential for optimal heart health, and excessive marathon running at a consistently high heart rate can be detrimental.
Yeah. Uh, but, but I think you have to combine the 2 whenever possible so that you can- Yeah. really give your heart its best shot. Interestingly, if you are like a marathon runner-Mm-hmm. And its people that run at a very high heart rate all the time. Yeah. That actually can work against you. Thank you.
[26:26-26:48]
Sustained high heart rates can lead to a decrease in free T3 thyroid hormone production, as the brain attempts to regulate the hearts rhythm.
And you actually lower your production of a thyroid hormone called free T3. Your free T3 levels go down. Why does that happen? Because your brain is saying, Hey, your heart rates too high for too long a time. Were gonna lower your thyroid hormone, because thyroid hormone is what- what stimulates the rhythmicity of the heart.
[26:48-27:10]
Over-exercising can cause heart enlargement and fibrosis, which are often monitored in distance runners through specific markers.
Right. And, but it, but the problem is theres a side effect to that. Right. Meaning that over a period of time, you get enlargement of your, of your heart. And thats why with a lot of distance runners, they measure things, um, troponin and, and, and galactin to find out, well, is there any fibrosis going on because youve, youve overdone it. Right. Stop Over-Exercising! Protect Your Heart & Thyroid!](https://i.ytimg.com/vi/q5Zp4qXxxZI/mqdefault.jpg)








