Jumping into the sea ?

[dram]

A mate on holiday in Spain saw a guy aged about 60 jump into the sea from a boat and the guy took a turn ie he had to be pulled out and it looked as though he was being treated for a heart attack. My mate assumed that the guy had a shock with the water temp...
I am in my 50's , reasonably fit & healthy and spend holidays in Turkey jumping from boats into the Med like a lot of other tourists ...
With air temp around 30C is it safe to jump into the sea as I must admit the initial shock of jumping into the water can be very breathtaking ..?
Thanks
Brian..

[dram]

Thanks guys..
The ticker & health is all fine
Already have the floats and the other 'object' .....!!!!!
Cheers
B