many biological processes are nonlinear. consider sleep. sleep generally happens in 90 minute cycles where you go from light sleep to deep sleep to Rapid-Eye-Movement (REM) sleep. REM sleep is the most important.

the nonlinearity comes from the proportion of REM sleep in each cycle. the proportion of REM sleep increases in the later cycles. So the fourth cycle will have more REM than the third cycle. what this means is that sleeping 8hours is not 33% better than sleeping 6hours but rather much more beneficial. nonlinearity.

another example is learning. although a different kind of nonlinearity. what many students tend to do is single-block cramming. studying for 15 hours in the last couple of days before exams. what we know from neuroscience is that this is ineffective for long-term learning. what’s much more effective is smaller blocks of study spread over multiple days. what this does is better memory consolidation through sleep and spaced-repetition.

another example that i learned today is zone 2 aerobic exercise. the graph of benefit vs time spent on zone 2 is a sigmoid. for the first 10 minutes or so, there are almost no benefits. then the benefits start to accrue over some time and then they plateu after around 50 minutes.

biological processes are fascinating. but probably this is not how its taught. must be difficult having to push through the cram terms and process names.