Your heart is a muscle, but you don't want it to work like your other muscles. When you want to grow your biceps and make them stronger, you lift weights. The more muscle you add to your bicep, the stronger it gets. It also looks nice to have muscle tone.
You don't want your heart muscle to grow. When the heart muscle grows, it's a medical condition called hypertrophic cardiomyopathy.
According to an article from the American Heart Association, this happens when the muscle cells get bigger, causing the walls of the heart to thicken. It usually happens to the left ventricle.
Exercise can spike your blood pressure to 200 or higher, according to an article from Johns Hopkins Medicine. However, that's not the kind of increase in blood pressure that causes heart problems. It's only temporary. In fact, doing five sets of an exercise can lower your blood pressure , according to a June 2015 article published in the Journal of Strength and Conditioning Research.
A different study published in January 2015 in the British Journal of Sports Medicine showed that resistance training decreased blood pressure in people with metabolic syndrome. In other words, you don't have to fear a problem like hypertrophic cardiomyopathy because of the brief increase in blood pressure from weightlifting. In the long run you're actually better off hitting the weights.
There are benefits to resistance training beyond lowering blood pressure. For instance, a June 2018 study published in the British Journal of Sports Medicine showed that resistance training not only decreased blood pressure but decreased fasting insulin and insulin resistance. Both can cause heart problems and increase your risk for diabetes.