The fourth most common death in Ireland is COPD or Chronic Obstructive, Pulmonary Disease.
A group of 50 cyclists are raising funds and awareness for the condition on a two day charity cycle across the country.
They left Galway yesterday and will arrive in Dublin later today.
Mullingar woman, Caroline Connelly, was diagnosed with COPD five years ago.
She says smoking is a major contributor to developing the disease.
"Give up smoking that's the biggest one thing you can do, don't be foolish.
"I didn't, I kept smoking and I kept smoking and then I gave them up, and I'd have a sneaky fag, and I'd convince myself that I was off them.
"Give up smoking, throw them in the bin, walk away from them, just give them up, do it," she said.