While most people would get these hours in overnight, it was also acceptable to "top up" with a nap during the day, as long as you felt naturally sleepy, Signal said.
Having a good night's sleep is particularly difficult for dairy farmers, who often wake up around 4am to start work on-farm.
Humans weren't designed to go to bed earlier than 9 or 10 o'clock at night, which made it even tougher for dairy farmers to get in a full eight hours, Signal said.
"We're just hard-wired to sleep at night, but if you have to get up at 4 you need to recognise that you're cutting into the sleep you're getting."
This is where "topping up" with naps during the day would be helpful for dairy farmers, especially around 3 to 5 o'clock in the afternoon, when people tended to have a "natural decrease in alertness," Signal said.
"I know farmers are busy people, but you've got to realise that sleep's incredibly important to your safety and wellbeing on the farm.
"So if you're not getting enough sleep at night, look at those afternoon opportunities as a point in time - even if you only get 20 or 30 minutes - to help top you up and keep you going."
While it "might not feel particularly great afterwards immediately", a short afternoon nap would still help farmers function much better for the rest of the day, Signal said.
Another obstacle in getting a decent sleep is trying to shut down the brain before bedtime.
Unfortunately, there was no magic cure for this but Signal had some handy tips to try and tire active minds.
She said it was important to remember that it was normal to feel this way.
"It's a normal human thing, you're really tired, you climb into bed thinking you're going to fall to sleep straight away but bing! the lights go on and you're wide awake."
Having a piece of paper and pen beside the bed to write down plans for the next day was helpful, along with trying to keep "worry and work out of the bedroom", Signal said.
Environment also played an important role in making a bedroom a "safe place to sleep" and Signal advised it should be "cool, dark, quiet and comfortable".
However, if none of this worked, it was best to get up, Signal said.
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"If you're really struggling to sleep after 30 minutes, get up, go into another room and do something quiet - which does not involve scrolling through Facebook and using devices - until you feel sleepy and then go back and try and sleep again.
'We don't want to make the bedroom a place where you get anxious or worried about falling asleep and lie there staring at the ceiling for long periods of time."
Another sleep issue was waking up a couple of hours before the alarm went off.
This was perfectly normal and not something to worry about, Signal said.
She recommended the same steps for being unable to get to sleep, writing things down, or getting out of bed to do something quiet.
Balancing a good night's sleep with quality family time was also difficult, but it was important to understand how a lack of sleep affected other aspects of life, Signal said.
"We often think if we cut back on sleep we can fit more into our everyday lives and it just doesn't work like that."
Waking functioning was reduced without a good quality sleep at night, Signal said.
"We are moodier, we are less communicative and we're not as much fun to be around. So you need to strike that right balance."
However, perhaps one of the biggest barriers to sleeping was due to a partner snoring.
This was a very common issue but loud snoring and pauses in breathing and gasping for air meant that person should probably have a chat with their GP, Signal advised.
Farmers can find out more about how to sleep well at Farmstrong's website.
