Time Depends on Intensity

Moderate-Intensity Activities:
Walking briskly
Golf, pulling or carrying clubs
Swimming, recreational
Mowing lawn, power motor
Tennis, doubles
Bicycling 5 to 9 mph, level terrain, or with a few hills
Scrubbing floors or washing windows
Weight lifting, Nautilus machines or free weights
Vigorous-Intensity Activities:
Racewalking, jogging or running
Swimming laps
Tennis, singles
Bicycling more than 10 mph, or on steep uphill terrain
Circuit training
Information from http://www.cdc.gov/nccdphp/dnpa/physical/measuring/examples.htm