And breath!
BP should be taken at the same time each day. DH and I were advised B4 eating each morning, the best of 3 readings leaving a few moments apart. His brother has recently been advised to take readings 3 times a day

- it appears that he was over medicated!
Heat. Hunger. Anxiety may all impact on BP levels. 1 cannot be aware of raised BP in the same way as it being low, i.e. sudden light headedness on standing from a sitting position.
Yep age can affect our health. Some medications can impact too. If U are taking anything do read the leaflet with each as it may/not indicate whether BP is likely 2 B affected.
I suggest that if you aren't feeling faint then take readings at the same time each day 4 a week then let your GP/Nurse Practitioner know.