Original Post:
Personal Experience:My Facebook wrote: Oh, so according to the AMERICAN HEART ASSOCIATION, high intensity interval cardio is bad for you? Despite the density of medical and sports literature to the contrary... I have an HRV in the 60s, a VO2Max in the upper 40s, a resting heart rate that can dip into the upper 40s (when I lay off the caffeine, lulz), perfect bloodwork, and I even did a couple miles of light cardio WHILE INFECTED with COVID and had an echocardiogram and stress test afterwards that both came back perfectly fine... and this is with no more than 20 minutes of cardio a day, focusing more on resistance training! #hiitworkout #hiittraining
So what does the literature ACTUALLY say about cardiovascular exercise modality? How does HIIT compare to the moderate intensity endurance training that these people are obsessed with?
1) Superior heart rate variability benefits:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6069078/
2) Meta-analysis of 7 trials found HIIT was superior at:
a. improving brachial artery vascular function
b. reducing cardiovascular risk factors
c. increasing insulin sensitivity
d. reducing oxidative stress
https://pubmed.ncbi.nlm.nih.gov/25771785/
3) Increased muscle mass:
https://pubmed.ncbi.nlm.nih.gov/28647284/
While it has been known for years endurance training impairs hypertrophic muscle gains:
https://link.springer.com/article/10.10 ... 011-2112-z
4) Superior at reducing blood pressure:
https://pubmed.ncbi.nlm.nih.gov/32125550/
5) Superior at burning calories:
https://pubmed.ncbi.nlm.nih.gov/25162652/
6) Superior at increasing VO2Max:
https://pubmed.ncbi.nlm.nih.gov/32083390/
MEANWHILE, excessive endurance exercise and competing in marathons are being increasingly associated with transient and potentially long-term damage to the heart:
1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6179786/
2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3538475/
3) https://pubmed.ncbi.nlm.nih.gov/270940/
4) https://www.sciencedirect.com/science/a ... 4619301516
5) https://journals.physiology.org/doi/ful ... 01151.2009
6) https://pubmed.ncbi.nlm.nih.gov/15377277/
But yes, if you would like to waste 10x more time running away your muscle mass for fewer benefits with higher potential for adverse cardiac events, follow the American Heart Association's idiotic guidelines... Don't run too fast! Just run all day long!
...and just remember, these people are a part of the same government-sanctioned establishment that tells you eating shitty foods in "moderation" and staying at home in a mask is a better strategy against COVID than getting out and running in the sunlight for vitamin D, training at the gym, and avoiding processed and sugary foods that reduce insulin sensitivity and cause metabolic syndrome...
PS: Fact check THAT, Facebook.
I transitioned from moderate-intensity cardio to a HIIT program probably about... 10 months ago now. At first it was insanely challenging to pull my big 185lb muscular ass up the big hills I was running through to hit the heart rate target. I would basically be done for the rest of the day afterwards... No way in fuck could I do weights with it.
Fast forward just a few weeks, and suddenly I was brimming with energy, I looked forward to the runs, and I could easily do rigorous weight lifting in the evening after doing HIIT in the morning. There are all kinds of reasons why weight lifting and muscle mass have been traditionally underrated and are extremely important health parameters (topic for another thread), and I can tell you definitively that a HIIT routine such as this plays better with weight lifting. You will not run off your muscle mass as with excessive endurance training. You are not eliciting competing mitochondrial and muscle tissue adaptations. You are not spending so much time doing cardio that you have no time to be at the gym. You can get the benefits of a cardio routine in a far smaller window, allowing you to focus more time and energy on other forms of exercise.