I have noticed that after intense workouts, particularly late in the evening (6 or 7pm starts, ~1hour or more), that my incredibly regular morning movements are either very small, or do not happen at all when I would expect my food from breakfast, lunch and snacks to be present at the least.
It is my understanding that the small intestine absorbs the majority of nutrients, and the large primarily absorbs moisture left from the solids and helps with gut fermentation.
Is it a case of the intestine trying to squeeze more out of the residue, or is the stomach utilizing more of the food that would normally be sent to waste?
Are you eating enough those days? I’ve noticed smaller bowel movements if I’m running a caloric deficit. But, I also don’t have routine bowel movements, having one at the exact same time of day would blow my mind lol.
Could be a number of things. Make sure you’re eating enough off the bike, unless you’re trying to lose weight. Have you always done workouts at that time of night? Maybe you’re dehydrated a little at night?
It could be a million thing but for sure make sure you’re eating enough fiber off the bike and complex carbs with proteins and fats.
I notice my routine is off normally during/after I travel or don’t eat enough. I have a schedule, every morning after coffee and then in the afternoon usually around 1.
The most obvious cause is dehydration. With evening rides its hard if not impoasible to get back to equilibrium without being up all night peeing. Even with fiber, if you are getting dehydrated it will be small/hard
I drink nearly a gallon of water between straight water and drink mix while on the bike, so I really am certain fluids is not the culprit. The lack of BM is strictly present after intense workouts in the evening.
You can’t “stay hydrated” during a ride, especially if it’s a hard ride, especially if it is indoors. You are losing all sorts of stuff even with optimal replacement, and even then it doesn’t just magically go to all the right places. Under those circumstances, your large intestine compensates by pulling in as much water as it can. The stool doesn’t then get re-hydrated when you drink a gallon of water - once it is dry, hard, small, it stays that way until it passes.