But half an hour later he was being whisked to hospital in an ambulance, where doctors told him he was having a heart attack.
Mr Whyte, 58, of Piershill, believes he could have died if his daughter Vicki, 29, had not persuaded him to call for help.
Now the pair are starring in a national British Heart Foundation advert, which features the voice of Oscar-winning actress Imelda Staunton. Directed by Saul Dibb, the acclaimed director of The Duchess, their story will be broadcast across the country over the next few weeks. They hope to raise awareness of the symptoms and causes of heart disease.
Mr Whyte, a housing support organiser for the city council, said: "The heart attack just came out of the blue. When I got to hospital, I honestly thought I wouldn't get out of there alive.
"I think it's really important to get the message across. The British Heart Foundation has been great at giving support and advice, so I was keen to give something back to them."
Mr Whyte had come home from work as usual in May 2008, and had gone to the supermarket to buy groceries with his daughter. When he got home, he told her he was in pain.
He said: "I had this excruciating pain in my left shoulder. I'd never felt anything like it. But I wasn't particularly concerned. People say you feel a crushing pain in your chest or shortness of breath, but I didn't have any of that.
"Vicki persuaded me to call NHS 24, and they sent an ambulance immediately. When I got to hospital, within minutes there was a cardiac nurse and a cardiologist."
Four days later, Mr Whyte was released from the Edinburgh Royal Infirmary. Since then he has completely changed his lifestyle, losing four stone in weight and exercising every day.
He said: "I was pretty inactive and I'd be the first to admit that I was overweight. Now I haven't had a fish supper in two years, and I have a brisk walk every day."
Ms Whyte, who also works for the city council, said: "It was a shock to the whole family. We're just very lucky they caught it early."
The pair were approached by the British Heart Foundation Scotland after they shared their story on its website. They spent several weeks travelling back and forth to London to film it.
She added: "We both thought it was really important to take part in the advert. I think it's really simple and effective.
"Some friends have remarked on it, but I don't expect we'll get recognised in the street."
The charity is encouraging people who have been affected by heart disease to call for a free Heart Information Pack. They can also sign up to the free Heart Matters scheme, and receive regular communication.
Marjory Burns, the foundation's director, said: "The power of Bill and Vicki's story, and their raw emotion, is much stronger than any actor could have given us."
For more information visit bhf.org.uk. The Heart Helpline is on 0300 330 3311.