Instant Heart Rate by Argus
Instant Heart Rate uses your cell phone’s camera to take your heart rate. Surprisingly accurate. FREE from your cell phone app store.
Insight Timer by Insight Network Inc
Insight Timer – a meditation app which can be set to remind you to do short breath holds at any interval you want. An invaluable tool! FREE from your cell phone app store.
$14 – $hundreds (professional quality)
Pulse Oximeter – there are multiple choices on Amazon and even in your local pharmacy.
A pulse oximeter is more accurate than the Instant Heart Rate, but is also not free. If you buy the least expensive, be sure to read the reviews before you make a decision.
Music To Help Slow Your Breathing and Calm You