MTB

I bought a Mountain Bike with 24 gears, the plan is commute to office and home with it. Today, the weather was very good (I trust the forecast), I thought of making a biking trip. Accompanied me was my flatmate. We made 26Kms, an enjoyable ride in the evening, at a cost. What is that, "I am dead TIRED and exhausted, now preparing to hit my BED".