A steam room, sauna, or hot bath is a great way to extend a heat session that is started by cycling or running. This plot shows what that might look like. The athlete started on the indoor trainer in a CORE suit and collected about 25 minutes in his heat training zone, with a Heat Strain Index between 3.0 and 4.0 during.
He then moved to a steam room (40° C/ 104° F) for another 30 minutes. With a normal resting heart rate of 50 beats/minute, his heart rate staying above 100 bpm indicates the heat stress he was experiencing. His Heat Strain Index peaked at 8.0, and he reported that was ‘very uncomfortable’. At the end of the steam session, he resisted the urge for a cool shower and his core temp and Heat Strain Index remained quite elevated for another 20 minutes.
This was likely a case of ‘overdoing’ the heat session…letting core temp and Heat Strain Index rise too high in the steam room. The athlete reports that in subsequent sessions he reduced the temperature of the steam shower and shortened its duration. Without the ability to monitor core temp in real time (from fear of steam damaging his watch), he monitors heart rate and cools off when it gets too high.