can being in the sun causes high blood pressure?

we live in gulf as u all know the temprature here is very high in summers my husband tried to do some work being exposed in the sun for about 20+minutes on the terrace when it was the hottest time of the day temprature must not be less than 50 degrees he came inside the room and went to sleep for about an hour and a half coz he was complaining some discomfort in head and next day after coming from office he complained his head is spinning so he reported sick and his bp was 152/85 its 3rd day and his bp is still high which he has never had in his life he is 58 years old his normal bp which last he took about a month back was 120/65 even his routine ECG was also ok which was done about 6 months back can some one please advise or tell me what has happened can being in the sun cause high blood pressure or is it coz of some thing else?

Unlikely the sun exposure caused high blood pressure, probably already had it. His symptoms you describe are simple heat exhaustion, (heat stroke is a more serious, immediately life threatening situation). Heat exhaustion does overheat the body, and causes some electrolyte problems due to dehydration. He should get over those symptoms in a few days with adequate rest and hydration. The high blood pressure, though not that high, needs to be treated by a doctor.