how strong are gastric staples ? Can they withstand straining on emptying bowels cough etc

They’re pretty strong. If they failed easily after surgery from simply straining while pooping or coughing they wouldn’t use them for any surgery. If they fail you’d have to have done something much more strenuous to your abdominal/upper digestive area or put a lot of strain on your tummy. If you follow the staged return to eating, not lift anything heavy before you’re allowed & don’t do any strenuous or jerking activities, you should be fine.

Staple failures are very rare.

Reassuring thank you- my main concern is sustaining straining when constipated

57 minutes ago, Fars said:

Reassuring thank you- my main concern is sustaining straining when constipated

Don't let it get to that point, if you can help it. Make sure you have plenty of fluids, fiber, and MiraLax. In the very beginning, I needed Miralax in the morning and a stool softener/laxative combo at night. I did that for the first 6 weeks, then I was able to just use the Miralax everyday. But the last thing you want, especially in the first 6 weeks, is to be straining. The staples will be fine, but it's the healing from the surgery and the pain the straining can cause that you want to avoid.

I am
Having miralax once a day but haven’t had an urge to go since four days - what was the night combo you used?

10 hours ago, Fars said:

I am
Having Miralax once a day but haven’t had an urge to go since four days - what was the night combo you used?

I used this, and took 4 each night:

https://www.walmart.com/ip/Equate-Stool-Softener-Plus-Stimulant-Laxative-Tablets-for-Constipation-240-Count/781701121

Also, some people find it helpful to hold a pillow against their abdomen when coughing to offer a little support. Worth a try.