Artist Susan Sills was not surprised that she first noticed hand tremors when she was 72 and a neurologist confirmed that she had Parkinson's disease.
Both her mother and grandfather had this neurological movement disorder. She knew that it sometimes runs in families.
But to watch her in action three years later, it would be hard for a layman to tell.
She stands straight, walks briskly, speaks in clarion tones and maintains a schedule that could tire someone half her age.
Sills, who lives in Brooklyn in the United States, attributes her wellbeing partly to the medication she takes, but primarily to the hours she spends working out with a physical therapist and personal trainer.
They have helped her develop an exercise regimen that, while not a cure, can alleviate Parkinson's symptoms and slow down the progression of the disease.
"The exercises opened me up," said Sills, adding that the regimen led to symptoms such as small steps, slow movements and tiny, cramped handwriting subsiding.
Ms Marilyn Moffat, a physical therapist on the faculty of New York University, said: "The earlier that people begin exercising after a Parkinson's diagnosis and the higher the intensity of exercise, the better they are.
"Activities that have been shown to be beneficial include cycling, boxing and dancing, as well as walking forward and backward on a treadmill."
The typical delay in starting an exercise programme stems from the ability of medication to alleviate symptoms, leaving patients with little incentive to exercise.
While everyone can benefit from exercise, it is especially important for people with a progressive movement disorder like Parkinson's that can result in weakness, stiffness, difficulty in walking, poor balance and falls.
For such patients, regular exercise tailored to their needs can result in better posture, less stiffness, improved flexibility of muscles and joints, faster and safer walking ability, less difficulty performing daily tasks and an overall higher quality of life.
Patients who take part in exercise programmes designed to mitigate symptoms and, perhaps, delay the progression of Parkinson's "can function independently at a higher level, have stronger feelings of wellbeing and are happier about their quality of life", said Ms Moffat, who has seen major improvements in people she has worked with.
Among the exercise options is an agility programme that incorporates the principles of taiji, boxing, pilates, lunges and kayaking. It was developed by Laurie A. King and Fay B. Horak at Oregon Health and Sciences University.
The agility course includes navigating turns, doorways and hallways; walking with knees high and hands touching them; skipping; and shuffling from side to side.
Other programmes include ParkFit, which fosters a more active lifestyle; Dance for PD, which has classes in New York City and other countries; and Microsoft Kinect Adventures, which uses Xbox games geared to different stages of the disease.