[nalle4]

Athletic Heart Syndrome – a side effect of low-intensitive training?

I have a background in Alpine Racing in my youth, although it is some years ago since I am 51 year now. I have not much experience in endurance training at race level, but I have always exercised to be in shape for my winter ski tours as well as for some recreational climbing. During the last decade I have suffered from a reoccurrence of my childhood asthma, a slight overweight (BMI of 27) and also some stressful working conditions. Before reading and adapting the training regime in UA, I have had severe issues with training induced fatigue (did most of my training in Zone 3-5), limiting my training load down to 2-4 hours per week.

During the spring I adapted the low-intensitive regime for a base period, and the results was remarkable. The exercise-induced fatigue is totally gone, and I feel energized to exercise. I have doubled my weekly training load to approx. 9 hours/week, I have dropped 20lbs in weight and my asthma is way better.

However, when I now tries to introduce harder workouts in zone 3-5, I have issues in getting my heart rate up. Previously, my maximal heart rate have been exactly according to the formulae 220-age. When competing earlier in 10k running races and shorter skimo races (approx 2 hours), I usually had a sustained heart rate of 90-95% of my max HR (average HR in 10k and HR during uphill sections in Skimo). Today, I struggle to get the HR up to Zone 3 (80% of max HR), and I barely am able to get it to Zone 4 (88% of max HR). I have not reached Zone 5, despite several maximal attempts, the best I had achieved is a heart rate of 161, still 8 beats away from my calculated max HR and still in Zone 4.

I have also noted that my resting HR have dropped during this period, from low 50’s to low 40’s. I have not experienced any other side-effects from the training regime, such as fatigue, and my performance on my sessions at zone 1-2 is the best for decades.

Consequently, I wonder if my issues with low heart rate and especially the inability the reach higher heart rate a sign of the Athletic Heart Syndrome (AHS)?

Any ideas on how to adapt my training, should I introduce more zone 3-5 sessions to adapt my body to higher efforts and HR, or am I risking to ruin my aerobic base in doing so?

Any opinion, or similar experience, is highly appreciated!

Topic

[Anonymous]

Anonymous on October 28, 2019 at 5:24 pm #30888

Your experience with a high volume of low intensity training is exactly what one would expect. You’ve seen dramatic gains in basic aerobic capacity which is a vital component to build on top of with some intensity. Your drop in resting HR is also consistent with what we expect. The reason you can’t get your HR up as high as before is due to 2 things. First is age. max HR typically drops fast for most folks after 50. The second is that; from the sounds of it you’ve been exclusively focused on Z1-2 training. You’ve lost your top end. That’s OK because that’s relatively easy to get back by just introducing more Z3-4 workouts. However, I’d do our Anaerobic Threshold test to find the top of Z3 currently and reset zones.
Scott

[nalle4]

nalle4 on October 29, 2019 at 8:29 am #30915

Thank you for your help and thank you for sharing the knowledge in your books, it has been a gamechanger for me to finally solve my issues with fatigue. I agree that my aerobic capacity has dramatically improved. I run half-maraton distances now in two hour pace while staying in zone 1, and I am almost more energyzed after the run, amazing!

Good idea to test AeT/LT/FTP, I will do that and continue to introduce zone 3 and 4 sessions. I’ll share the results.