One month before I completed a 3.7 km open water race with air temperature 21°C and water temperature 25°C and I was feeling great, so my next target would be 5 km. Therefore I decided to try doing a straight 5 km non-stop in a safe environment and get a time for myself Sunday afternoon. I measured two easily-recognisable points at a curved beach on Google Maps which were 424 m apart, and decided to swim 12 of it, i.e. getting about 5.1 km in total. The air temperature was 25°C and water temperature was 23°C. I started around 2:50 PM and finished around 5 PM Sunday. However, in the morning I also had another training session of about 2.5 km (around 9 AM) and an orienteering race (around 12 noon).
However, I got sick immediately after the swim. When I completed all 12 laps, I felt my lats were so fatigued to the extent that I nearly felt pain. More importantly, when I started cooling down as I normally did, my thermoregulation went wrong and I started feeling cold and shivering despite 23°C water temperature (normally I could stay in 21°C water for more than an hour without getting cold, and these kind of effects normally happens on me only when the water temperature is under 19°C). The shivering only stopped when I put on my clothes in the changing room.
I then developed flu-like symptoms including fever, sore throat and extreme tiredness, along with extreme lats fatigue. I had to return to bed immediately after getting home and skipped dinner (~ 7 PM Sunday). The sickness and lats fatigue were gone around midnight, but I still had a little sore throat and I felt not completely recovered yet in the squad training on Monday morning.
Now I am worried if I am demanding too much for myself. My target for this winter is to complete 5 km within 2 hours in 16°C water (the lowest water temperature in my region which comes in February) in standard swimming costume (if I can do this 5 km in this winter, i.e. 2018/2019, I would like to try 15 km next winter, i.e. 2019/2020). However, if swimming 5 km makes me sick in 23°C, how the heck I can do it in 16°C?! I also wonder why my lats were so fatigued after that 5 km despite done a 3.7 km race one month before - was it because my morning swim affecting me in the afternoon?
The weather forecast is predicting 14 - 16°C air temperature with rain in the coming weekend, by that time the water temperature will probably become around 20 - 21°C. Should I continue to do 5 km training or to reduce a bit, e.g. to 3 km?
That is true, with some severe caveats. Over training impairs the immune response, among other deleterious effects. i don't know of any reputable recommendations to exercise hard if you have a systemic illness. If you do, please give a citation.
OP's case wouldn't classify as systemic, but regardless, here's just one quick source showing that vigorous exercise helps fight off viruses. And I'll also refer to my previous reference. www.bbc.com/.../health-26581722
The only stuff I've seen about weakening the immune system requires cumulative sessions of overexercise.
That is true, with some severe caveats. Over training impairs the immune response, among other deleterious effects. i don't know of any reputable recommendations to exercise hard if you have a systemic illness. If you do, please give a citation.
OP's case wouldn't classify as systemic, but regardless, here's just one quick source showing that vigorous exercise helps fight off viruses. And I'll also refer to my previous reference. www.bbc.com/.../health-26581722
The only stuff I've seen about weakening the immune system requires cumulative sessions of overexercise.
