When 40-year-old Rachelle Smith began feeling so exhausted after work that all she could do was collapse onto the sofa, she brushed it off as a normal, inevitable part of midlife.

Previously, she'd spend hours playing sports or hitting the gym.

Now, even fun social events seemed onerous – and cancelling on plans became a regular occurrence.

'I'd arrange to go for coffee or horse riding with friends and pull out at the last minute,' says Rachelle, a stunt performer from Wales.

'I lacked the motivation. I didn't want to do anything – it was like my entire personality had changed.

'I started taking naps during the day – which was completely unlike me – and found myself just trying to get through each day and focusing on getting home and going to sleep.'

To add to this, she began to suffer from aching joints, irregular periods, trouble focusing and memory lapses, leading her to turn down work because she was too exhausted.

'My mum went into an early menopause, so I assumed this is what was happening to me too,' she says.

Rachelle Smith, 40, brushed off her intense fatigue and brain fog as a normal part of midlife

Since discovering the root cause of her symptoms, Rachelle has taken up her old hobbies again

Menopause symptoms typically start during perimenopause, which often begins when a woman reaches her forties. This happens as hormone levels fluctuate in the years before periods stop completely.

But when Rachelle began looking more closely at whether the menopause could explain her symptoms, a friend's recommendation to take an at-home blood test pointed to something else entirely – and an easy solution that gave her her energy back.

The finger-prick blood test Rachelle used, called the YorkTest Essential Health Check, revealed she was severely deficient in iron and vitamin D, while her vitamin B12 levels were also on the low side.

And she isn't alone. Around one in three women experience iron deficiency at some point in their lives, with heavy menstrual bleeding one of the most common causes.

If severe iron deficiency progresses to anaemia, it can reduce the blood's oxygen-carrying capacity, placing extra strain on the heart and, in rare cases, contributing to complications such as irregular heart rhythms.

Iron and vitamin D deficiencies often occur together and can share overlapping symptoms, including severe fatigue, muscle weakness and low mood.

Some studies suggest that heavy perimenopausal bleeding can trigger iron deficiency anaemia, while low vitamin D has also been linked to fatigue, muscle weakness and low mood.

For Rachelle, discovering she had multiple deficiencies came as a shock.

'I really underestimated how much nutrition can impact your life,' she says. 'That's why I assumed it was a hormonal problem; I didn't think a vitamin deficiency could cause such extreme symptoms.'

Professor Toby Richards, a surgeon and iron deficiency specialist from the University of East London, explains that while at-home tests are good for screening, they cannot replace formal clinical blood draws and professional diagnosis.

The good news is nutrient and vitamin deficiencies typically improve within four to 12 weeks of starting targeted treatment.

'I started Googling how to fix this and realised that because I'm vegan, the plant-based iron I'm getting in my diet is harder for the body to absorb,' says Rachelle.

'Now, I actively try to eat more vitamin C found in fruit and veg such as red peppers and oranges – to increase my iron absorption.'

Iron is the hardest deficiency to correct through diet alone because the body tightly controls how much we absorb. Although absorption increases when stores are low, diet alone often isn't enough to replenish them.

Even if you start eating more iron-rich foods, a deficiency usually still needs supplements. That's especially the case if heavy periods or gut issues are driving the loss.

On advice from a friend, Rachelle started using iron and vitamin D supplements in the form of oral sprays as she struggles to swallow pills.

Vitamin sprays, such as those Rachelle used, are sprayed onto the inside of the cheek or under the tongue, where they are absorbed through the mouth's mucous membranes into the bloodstream.

Because some of the nutrients can enter the bloodstream directly through these tissues, they may bypass much of the digestive tract. This can be helpful for some people with digestive conditions that impair nutrient absorption.

Clinical studies on vitamin D supplements show that oral sprays raise blood levels just as effectively as standard capsules or tablets.

However, experts have raised concerns about how effective oral iron sprays are because they deliver much lower doses of iron than standard tablets and lack robust clinical trials proving they can treat iron deficiency anaemia.

Instead, Professor Richards recommends using 200 to 300 mg of oral iron, either in liquid or tablet form, taken for three to six months, before repeating blood tests and reassessing.

He also advises that women who don't eat meat should take a low-dose iron supplement either every day or on the days of their period to supplement and maintain normal iron levels.

Rachelle says: 'The best thing is that these lifestyle tweaks have been really easy to incorporate into my routine.

'It's such an easy fix and doesn't have to be a difficult, massive change.'

Rachelle had so much more energy that she took up horse riding after work - something she hadn't done in years

Rachelle's energy levels have also been restored.

'Within two weeks, I felt like a different person,' she says. 'The fog lifted. I started running and I even took up horse riding again after work – something I had not done in years.'

Rachelle's advice to others is not to underestimate the importance of what's on your plate.

She adds: 'The easiest thing to fix is diet, especially as you're getting a little bit older and your body might require a bit more energy from these things.

'Even if you think you're getting everything you need from your food, it doesn't hurt to get your levels checked out if you're exhausted all the time – things like iron and vitamin D are such an easy fix.'

While her friends are happy that Rachelle is spending more time with them, the person who has seen the biggest change is her husband.

'It had got to the point where he was always worried about me and trying to care for me,' she says.

'Now we've both got our lives back and I feel much more independent, like the woman he married.

'I'm just so pleased that it wasn't just my age kicking in and there was something that could make my horrible symptoms go away.'