Sherwani, who won gold with Great Britain at the 1988 Summer Olympics in Seoul, South Korea, said he expects to eventually be unable to remember his sporting achievements.
He scored two goals in the men’s hockey final against West Germany, one of the most memorable moments from that year’s Games.
“Where, oh where were the Germans? And frankly, who cares?” screamed BBC commentator Barry Davies when Sherwani scored GB’s third goal in its 3-1 win.
Sherwani, 59, said he was diagnosed with the disease in 2019 but first noticed signs seven years ago.
“At first my mood changed and I became withdrawn. I wanted to be on my own and not talk to people,” Sherwani said.
“Eventually it got to the point that I was on the edge of breaking down because the situation had put such a strain on me, so I went to the doctor.
“That led to a three-year journey of tests and brain scans until I was eventually diagnosed with Alzheimer’s disease,” he added.
Every day almost 600 people in the UK develop dementia, according to the charity Alzheimer’s Research UK, which has partnered with Sherwani.
There are over 850,000 people in the United Kingdom living with dementia, according to the Alzheimer’s Society, with over 42,000 people living with young-onset dementia — people whose symptoms started under the age of 65.
Sherwani’s gold medal with the GB hockey team was one of five the country won in the 1988 Olympics.
It marked the first time GB had won gold in the men’s hockey discipline for 68 years.