BP cuffs come in 3 STANDARD sizes, small/medium/large for 90% of the population...then there are larger sizes for guys like us...and although your arm may fit into a cuff, the reading is going to be high...there is room for air to expand into the cuff and release thus allowing your BP to be taken...if there is too much or too little room to begin with, issues arise as far as accuracy...go to CVS and spend $20 or so and buy the all in one stethoscope/BP cuff...then you can take your BP all day and pretend you're a doctor or something too lol...it's really easy to take a BP if the stethoscope is placed in the ears the right way (yes they can be put in backwards making it very difficult to hear anything lol)...
if you have a cuff at home, here's how to take a BP...
1. wrap the cuff around the arm with the arrow running down the inside of the bicep in line with your ring finger (dummy proof artery listening spot)
2. tighten the knob on the squeeze ball (allows air to fill cuff)
3. pump until you reach about 200mm/hg on the gauge (always overfill the cuff)
4. slowly loosen the air control knob so that it releases air from the cuff (you want the air release to be very slow if you aren't good at it)
5. with the stethoscope in your ears, listen until you hear a beat (that's the systolic pressure - top number)
6. keep listening until you don't hear any more beats (once the last beat is heard, that is your dystolic pressure - bottom number)
wallaaaaaa...you are done!!!