Cardio exercise and plenty of sleep are very important. Cardio is one of the best things you can do. Being
overweight has a big impact too, so if you are overweight try getting that down.
I keep mine down naturally by taking 2 flaxseed oil and 2 fish oil supplements a day (one in the morning and one at night), an odorless garlic supplement, 50 mg of
Coenzyme Q10, a calcium + vitamin D and a
vitamin C, mixing in 2 tablespoons of flaxseed meal with my oatmeal in the morning, and drinking a carrot, apple, strawberry and banana smoothie in the afternoon. (I juice 2 carrots and an apple and then use a wand blender to blend in 1/2 banana and about 4 strawberries). Mine was about 157/99 at its highest and after doing this for a month it was basically down to normal.
Other things that are important are avoiding sugar and white flour (stick with whole grains and natural sweeteners like honey,
stevia, xylitol or
agave nectar) and avoiding too much salt, which is especially high in processed meats (lunch meat, bacon, etc.). Don't cut it out completely, your body still needs salt, but do try to cut down. Beet Juice is also supposed to be one of the best things for blood pressure but I haven't been able to stomach that.
Lowering your BP naturally is going to be much better than going on medication anyway because none of the things I mentioned above have side effects, and the prescription drugs do. Don't expect to see dramatic results immediately, it could take a few months to go back to normal. Good luck!