Please choose the correct ending to complete the given sentence: Health: [header] How to increase bdnf [title] Try biking. [step] Biking is a cardiovascular exercise that, if done regularly, will increase your bdnf. Bike three to four times a week for 30 minutes to an hour.

Ending1: Make sure to incorporate 10 to 20 minutes of fast-paced biking to increase your heart rate further. [substeps] Bike around your neighborhood or local park. Ending2: Biking will improve your cardiovascular muscle abilities, including improved strength. [substeps] Walk on a treadmill for 30 to 60 minutes with the solar psi machine. Ending3: If your conditions are serious or there is discomfort in your joints, wear loose-fitting, fashionable clothing such as long sleeves and underwear. A cycling backpack can help improve your posture. Ending4: Another type of cardiovascular exercise is jumping on your bike to increase your bdnf level. Try running for an hour every day for a week.

Answer format: ending1/ending2/ending3/ending4