After a certain number of divisions, the cells in our bodies stop dividing, becoming senescent which can, at times, secrete toxins that cause inflammation. Senescent cells have been linked to all manners of disease, from arthritis to Alzheimer's disease. For the research, scientists have zapped senescent human cells with low-frequency ultrasounds, which restarted division.
Turning their attention to mice, Professor Michael Sheetz, of the University of Texas, said: "I don't think rejuvenation is too strong a term."
Mice, aged between 22 to 25 months - equivalent to a human being in their 60s or 70s - were placed in warm water, deep enough to cover at least half their bodies.
The rodents who were treated with ultrasound waves in water performed better in physical tests than rodents who were not exposed to the sound therapy.
Ultrasound waves lose less power travelling through water than they do through air, the research paper noted.
Fluorescent dyes that light up senescent cells also revealed that treatment with ultrasound decreased the number of senescent cells in the kidneys and pancreas.
A possible biological explanation is ultrasound physically distorts cells, producing similar effects to exercise.
Professor Jurgen Gotz, of the University of Queensland, commented on the findings.
While not involved in the study, Professor Gotz said: "I think more work is needed to define the effective ultrasound parameters."
When applied to people, for example, he pointed out bones and lungs block ultrasound transmission.
Reportedly, a small trial is already underway to see if sound therapy can help people with Alzheimer's.
In theory, any therapy that boosts cell division could increase the risk of cancer, but Professor Sheetz and his team have seen no evidence of this in their research.
The first adjustment to make is to have a nutritious diet, full of herbs and spices.
"Obviously, you want to eat more greens and colourful veggies like beets," said Dr Fitzgerald.
Yet, she also recommends trying different "herbs or botanicals, like turmeric", which "have the ability to change our genetic expression towards something more youthful".
Another key element to biological age reversal is doing moderate exercise, which promotes cellular repair.
Dr Fitzgerald said results can be seen with "half an hour, five days per week" of exercise - as long as you're "breathing just a little bit more " or experiencing "light sweating".
Another factor is reducing stress levels, as stress can lead to premature ageing.
"Stress is like gasoline on the fire of ageing," said Dr Fitzgerald, adding that "engaging in meditation, or maybe yoga or tai chi" can have "really good effects".
"Sleep - if it's good quality, will keep us biologically younger," Fitzgerald said.