Heartbeat is 92 beats per minute. Total number of heartbeats is 3.1 x 10^9. (3.1 x10^9 beats)/(92 beats/minute)=33,695,652 minutes 24 hours/day x 60 minutes=1440 minutes/day 365 days/year x 1440 minutes/day= 525,600 minutes/year 33,695,652 minutes/ 525,600 minutes per year=64 years