The problem is the high blood pressure caused by the increased heartrate.
And yes, this does cause you to have an increased risk of another stroke after sex.
You need to be clinical and get a blood pressure set and check your pressure during these sessions. I am going to bet the upper number is over 200.
One solution would be to take a sublingual nitroglycerine tablet after sex. This will cause vasodilation, a redeuction in body capacitance, and drop your blood pressure.
In the meantime, reduce your weight and follow your physician's instructions in regard to blood pressure medications religiously.
This can also happen because of blood pressure... blood pressure changes during sex.
People who suffer from migraine headaches are prone to have "sex headaches"... headaches immediately after orgasm. Also, men are known to have this type of headache more often then women. So are those who suffer from high blood pressure. And those with a history of stroke.
Usually these headaches aren't anything to stress about... just like any other sort of headache like migraines or tension headaches. BUT it is still important to go to a doctor to discuss this, especially since this has developed over the last few months. So, please see a doctor to discuss this soon.
There are some things you can do to prevent these headaches during intercourse... these include stopping sex prior to orgasm (frustrating, I know... but, this is one option that some couple work into the sexual aspect of their relationship from time to time). Another option is to take a more passive role during intercourse, so basically, don't do the work, let her do the work ;) that can make a huge difference for a lot of people. Something that I personally find helpful is to make sure that I am not dehydrated or feeling weak or tired prior to intercourse... which can be hard to gauge in the moment... so, it's a good idea to just go drink a glass of water before you have sex to be safe! And, not to have intercourse too late at night... never when I'm exhausted. That's not anything a doctor ever told me to do... just something I've personally found that's helped me.
Both my boyfriend and I, who are both migraine sufferers, do get pretty severe headaches after orgasm on occasion. And... I'm 25 and female, and neither of us has had any history of stroke or heart attack... so really, this can happen to anyone. So, please don't stress about it and assure your wife that sex headaches can happen to anyone and are usually not a sign of a severe medical problem. BUT, with that said, please book an appointment to see your doctor right away. This is Especially important since you have a history of stroke.
AND, if you ever experience a headache that you would describe as "the worst pain you have ever felt in your entire life" or a very severe headache that you have never felt before that does not go away on its own within 12 hours or a headache that is accompanied by vision loss or what looks like a "veil" over your vision, or a headache with any neurological symptoms such as slurred speech, please go to emergency right away.
Hope that helps. I'm not a doctor or anything... hope you don't mind that I answered... I just have some personal experience (unfortunately!) with this, so I figured I might be able to give a bit of advice...
My friend when that shows means you have low oxygen on you blood, you need to check with a doctor
There are some people who get severe headaches after sex because they aren't getting enough oxygen and breathing during sex (I wonder why ? ; ^ ) ) Anyway, because of your medical history... I would consider getting a referral and seeing a neurologist.