You need to monitor your bp regularly as a single high value doesn't mean high bp. You also shouldn't allow any physical activity for atleast 10 mins before measuring bp. Increase in thirst is normal in this hot weather , esp after working in the sun.You may consult me personally for any further issues

Yes but as an in direct effect Drink enough water about 5-6 lits per day Systolic bp or upper limit as mentioned by you is just above mean of 140 mm hg is considered bp You can try Tab telmisartan 40 mg daily in the morning after food To bring bp to normal level.

Hello, yes dehydration does cause increase in BP. As body lacks water, brain makes your blood vessels constrict which increases your bp. hydrate adequately. take ors sachets(diluting in a ltr of water) for 3 days monitor your bp and other symptoms for few days. But do you have any other symptoms? What is your diastolic BP?  Does your bp become normal with proper hydration? Do you have any other comorbidities? Are you taking any medication currently?

No. dehydration is very unlikely can not cause high blood pressure. in the contrary it causes low BP. Sometime BP might fluctuate a little. A single high reading does not means you have high bp. keep on monitoring bp, drink plenty of liquids. You may take ORS powder also.