Her bp increase at mid-night to around 140 levels.in daytime its ok.doctor has advised bp medicines.why bp increase at night??what to do??

Nocturnal bp: Some people have their highest bp in the evening after the day's activities, evening meal, salt and possible caffeine intake or even more stress and anxiety. I don't think a bp of 140 itself warrants antihypertensive medication unless the diastolic level is over 80 or daytime bp is more than 140/80. Lifestyle modifications like salt restriction,weight loss if overweight,etc should be tried first.