Problem
A young athlete has trained over several months to participate in a short bike race. They are doing this with their good friend, and it's just for fun. They anticipate (based on their training times) that the total race will take them ~90 minutes to complete. The race will take place on a cool autumn day, and the individual expects to be performing at a steady state of ~50% of their maximal aerobic capacity.
I. What would be happening to the plasma concentrations of the following hormones within the first 30 minutes or so of the race (ie, moving from rest to a steady state):
i. Epinephrine/Norepinephrine
ii. Insulin
II. As time passes (ie, duration), what changes will be occurring to energy substrate oxidation (ie, what's being burned for energy CHO, Protein, or Fat)?
III. What would you expect to be happening to blood lactate concentrations over the duration of the race? (ie, between say minute 30 and minute 60)
IV. What if instead of a cool autumn day competing just for fun, this athlete raced in the middle of a hot summer day and at an intensity of ~85% of their maximal aerobic capacity? What would happen to their oxygen consumption and blood lactate concentrations over the duration of this race?
V. Immediately following the race, (ie, right after they cross the finish line and stop running) what will be happening to the athlete's oxygen consumption rates, and why?