He should lighten up his exercise just a bit to ensure he is not overloading his heart.
Underweight just use algebra
I just have to point out, chicken is never safe to eat. All animal proteins cause cancer, type 2 diabetes, high blood pressure, high cholesterol, migraines, high mercury levels, osteoporosis, arthritis, obesity, etc. etc. Chicken is especially unhealthy because of the salmonella contaminates in it. By the way, I think your answer would be below 40 degrees but I'm not positive. Just keep this in mind next time you eat animal products.
Since 2000, life expectancy has increased by 78.7 percent for the general population in the United States.