On the undergrad side, yes. There are programs to receive your Bachelor's degree in about 18 months to finish those requirements quickly.
On the postgrad side, my college was on the quarter system, so I took no breaks and finished 12 academic quarters in 3 years.
Many professional schools are on a trimester system now. With 3 per year, not taking a trimester break in a year will still finish your curriculum about a year quicker.
Therefore, if you did both of the above, instead of 8 years to become a doctor academically, you could do it in 4–5.
However, there is a required internship time, for example, to become an MD, which will add to that time.
Alan Bonebrake, DC Chiropractic Medicine, Palmer College Of Chiropractic (1980)
Source: Quora Digest