Geez, I wish I could get into phenominal shape by biking 15mins twice a day Coming from a 9-5 worker (on my feet/physical labour all day), if you are looking to get into decent bike form, i'd say aim for 1hr rides through the week with 1-2 hard sessions (intervals or race like efforts) and then some steady, longer rides at the weekend. Include 1-2 rest/recovery days (I like mon/fri). 8-10hrs a week is all it's ever taken for me to stand on the podium at races.