There isn't any legally imposed limit as far as we're aware, but a high blood pressure must be controlled with medication before you travel for your safety. For example, blood pressure is considered high if over 140/90mmHg, so if your blood pressure is consistently above this value then it is important to reduce it.
Being a pilot is not without its risks. Pilots must be aware of the physical and mental strain, the danger of accidents, the risk of job loss, and the potential for legal action. With the proper training and preparation, pilots can minimize these risks and ensure their safety and success in the air.
If it's still very high, seek medical care. Call 911 or emergency medical services if your blood pressure is 180/120 mm Hg or greater and you have chest pain, shortness of breath, or symptoms of stroke. Stroke symptoms include numbness or tingling, trouble speaking, or changes in vision.