Charles Kennedy has been reassuring Lib Dem MPs he will get fitter and inject more energy into his leadership.
Mr Kennedy showed signs of illness during Sunday's speech
Mr Kennedy's tried to quell speculation about his health in private meetings with Lib Dem MPs and peers.
He now intends to use Parliament's Easter break to get back to full strength with some hill walks.
Last week a violent stomach bug was given as the reason he could not attend the Budget and he mopped sweat from his brow during a speech on Sunday.
'Full time job'
Mr Kennedy tackled fears about his health head-on in private meetings with his MPs on Wednesday and Thursday.
He conceded he had learned through experience that party leadership was a "24-7" job.
Some Lib Dem MPs have been privately critical of Mr Kennedy's habit of relying heavily on a small number of trusted advisers.
Now, he has offered to adopt a more inclusive approach.
According to senior MPs and peers, Mr Kennedy's words helped to reassure party figures.
But BBC political correspondent John Pienaar said there was a private recognition in the party that Mr Kennedy needed to deliver on his promises - and perform well in the coming local and European elections - to silence the whispers once and for all.
Mr Kennedy told BBC News on Thursday: "Obviously, I had a health setback last week of a fairly severe kind, for which I had to take myself off to bed for several days and that is not something I want to see repeated.
"It was not very pleasant for me and it certainly was not very useful for the party.
"I've been hit by a bad bug and that really drains you. There is no doubt I want to restore my health to where I would like it to be and the recess is a good chance of doing that.
"I'm going to take to the hills in the literal sense of the word."
Mr Kennedy has denied having a drink problem and said his words were not a coded message about that issue.
'Drink problem' denied
Lib Dem peer Lord McNally said the media was more excited than politicians about the story.
He said Mr Kennedy had put in two very impressive performances at the party meetings.
Those had "reassured people that he's learnt one of the lessons which perhaps he needs to learn that leading a third party, without some of the assistance which goes to the official Opposition, is a 24-hour, seven day a week job in which you've got to look after your health".
Lib Dem backbencher Jenny Tonge has suggested he needed to consider if he was fit enough to carry on in his job.
But Mr Kennedy laughed off comments by Dr Tonge that he needed a "medical MOT" saying he always welcomed "helpful advice when it's delivered across the airwaves".