Rebecca,
here's a link to another LDWA thread which appears to give your problem; and a solution from Jeffrey W Treadway. It could possibly be 'Dumping Syndrome' - too much sugar in a rush.
http://www.ldwa.org.uk/forum/show_topic.php?tpc=633&dir=S

That's very interesting reading. A couple of times I have felt sick and dizzy after a walk (normally if it has been hot and I have run a significant portion of it) and my heart rate drops, sometimes to below 40 bpm - could this be due to excessive sweating and losing sodium? My GP couldn't understand it as he thought that dehydration would quicken your pulse rather than slow it down....

I meant to get back earlier. Cutting down salt means that I make my own bread without salt (in a bread maker), all preprocessed food is out. Cut down on cheese, all pickles, olives are INCREDIBLY high in salt. Eating out is very dicey. Holidays in hotels are very tricky. MY BP is always up after a holiday as there's no control over salt. Read ALL food labels. The suggested 6 grams of salt per day is much too high. I think 1 gram per day is a much better target. Often food manufacturers hide the salt by giving the only the sodium content; multiply sodium content by 2.5 to get the salt content. Don't forget that salt is necessary though.

Thanks for the advice John. The readings are about 175/95 on a morning and 135/82 on an evening. After a long walk it is below 120/80 but goes back up next day. She's cut down on salt but her breakfast coffee could be a problem. We'll try some readings before breakfast and see.

What sort of BP readings did and does, Kath have? A couple of years ago I found that my BP was 160/90 and the doctor wanted to put me on medication. I asked if I could control it with diet and was told to cut down on salt. I tried, but it made no difference until I discovered all the 'hidden' salt in my diet. Also I discovered that even small amounts of coffee could put up my BP. I've now given up coffee and cut down on most of the hidden salt, and my BP is now well inside limits, all without medication. I can give more details if you want.
I've also found that exercise does lower BP. I think it expands the arteries and capillaries, allowing freer blood flow; it's the heart squeezing the blood through those capillaries that is the raised pressure.

Do a 'blood pressure' search in Google custom search (top right hand corner)

http://www.ldwa.org.uk/forum/show_topic.php?tpc=143&dir=S

Thanks for the comment John. Kath has talked about this with her Dr and his response was that is probably due to her lowering her salt level because of sweating, which may of course be true.

Incidentally, we now wonder if the drop in BP after a walk is the reason some people feel faint and even pass out at the end of a walk.

Hi Geoff / Kath

I have not got any formal medical knoledge but the fact Kath is doing something she enjoys , would lead to her feeling less stressed and that could lower her blood pressure.
Might be a good idea though to discuss with who is managing her blood pressure as to mileage / elevation of your walks - especialy in the early days of getting it stabalized.

Kath is being treated for high blood pressure and this involves her taking the readings at home, twice a day. One thing we have noticed is that, after a day's walking, her readings are significantly lower; even down to "normal". I've been checking my own BP (not because it's high but in sympathy with Kath!) and have also noticed a drop after walking.

This seems to point to the fact that walking lowers the blood pressure but I'd be interested in the opinion of anyone with medical knowledge - Geoff.