Like millions of Americans, Joel Runyon's days are powered by a healthy dose of caffeine.

An endurance runner and fitness coach, he consumes anywhere from two to six cups of coffees' worth, depending on his workout regimen.

But after 'having trouble sitting still' and feeling constantly restless, he decided to take up a no-caffeine challenge that would see him abstain for 30 days.

The Texan had read about others who'd followed a coffee-free lifestyle, which is becoming increasingly popular, who said they felt more energized and had better sleep and concentration.

But after ditching it for 30 days, Runyon said he was disappointed by the outcomes. 'So what do I think of life without caffeine?' he said, reflecting on his mini-experiment in a video online.

'I think it's pretty much worthless. 

'I came into this actually thinking I was going to come off caffeine and level out and have like way more energy, way more clear-headed thoughts and just be like crushing it across the board.

'[However], what I noticed was that I basically didn't feel any benefits.'

Along with no benefits, Runyon said he was surprised to have no withdrawal symptoms.

Common side effects of cutting caffeine abruptly can include headaches, nausea, muscle pain, tiredness, difficulty concentrating and irritability.

But Runyon said he didn't notice anything different about his performance at work or in the gym.  

He tells viewers: 'I drink a lot of caffeine on a regular basis and I actually thought coming off of [it], I would have like a massive headache or the "caffeine hangovers" and that didn't even happen. 

'I just kind of came off at the beginning of the month. I just decided I was not going to drink it anymore... cold turkey... and it was totally fine.

'That was actually the the most surprising part, because I thought I would definitely definitely have a headache or a hangover or something.'