Anxiety, Bradycardia, and Genetics

I am a 35-year-old male. I do HIIT workouts several times a week along with strength training. My Apple Watch indicates my average resting heart rate is around 48 bpm over the last 6 months. When I sleep, it's not uncommon for it to be around 38 bpm. My resting respiratory rate is typically 8-12 breaths per minute. I mention all this because the following symptoms appeared right around when I started getting into shape. Around March 2025, I started waking up gasping for air. I can only describe the sensation as feeling like I am holding my breath without trying. It's ruining my sleep and slowly impacting my mental health. Over the past year, I've had the following tests run, and they have all come back normal. My doctors are at a loss: * In-lab sleep study * 2 At-home sleep studies * 14-day Holter monitor * Pulmonology evaluation * Endoscopy to rule out GERD * I had my genes sequenced by 23AndMe and I don't have any of the genetic risk factors for heart disease * My lab work is all normal Now, here's the interesting part. I recall my dad having something similar happen to him in his 30s when he was in peak physical shape. I spoke to him, and he said he had the exact same symptoms, and they only went away when he stopped working out. This raises a few questions for me that I'd love to hear the community's thoughts on: 1. I've read that some people with bradycardia need to "de-train" and stick to more strength training and zone 2 training. Is this true? If so, what do you recommend? 2. VO2 max is highly correlated with longevity. If my body essentially can't handle workouts that raise VO2 max, does that mean I'm doomed to live a shorter life? Other medical details that may be relevant: * I take 20 mg of Lexapro for anxiety. * I take 20 mg of Vyvanse for ADHD. * I have pretty bad GERD, but it's mostly under control.