Yes, you absolutely can. If you don’t have an hour a day, don’t force yourself to “squeeze” the full length of recording into your daily activities. This can create more pressure, and you will be missing the whole point.
15-20 minutes a day is enough, as long as you are being consistent about it. Consistency is the key ingredient to succeed in this process, the amount of time per day does not necessarily matter. However, if you do have 30-60 minutes a day to listen to the programs, it’s preferable, at least in the beginning, four week period.
Please note: It’s recommended to use the recordings at night, before sleep and/or during sleep. In this case, it should be easy to listen to the whole hour.