I tried Gemini's new 'Gems' feature to create my own custom AI fitness coach — here's what happened

Man and woman side by side lifting dumbbells in a plank position during a weights workout
(Image credit: Shutterstock)

Google is continuing with its Gemini offensive, rolling out the model to anyone without an account, using it to upgrade Google Sheets, and letting it summarise your documents for free.

Now, it's turning its attention to more personal AI models, with its Gem feature, which allows custom GPT-style companions, rolling out for all users — even free ones.

While I was tempted to create a gaming Gem, I've already written why Microsoft's AI Copilot on Xbox has me fearful for the future of my industry. Instead, I opted to create a fitness-focused Gem.

Setting the parameters

Google Pixel 9 Pro XL using the Gemini assistant

(Image credit: Tom's Guide)

I've spent the last couple of years working with a diagnosis of bradycardia, which impacts the rhythm of my heartbeat. In short, it doesn't beat quickly enough, and so I have to be mindful while I work out because too much can lead to dizziness.

I factored that into my 'Fitness Gem', leading with this text in the 'Instructions' box:

"You can help me with fitness and weight loss advice, being mindful that I have had health issues with my heart (bradycardia) in the past."

"I am 35 years old, 6 ft 5, and have been lifting weights 'on and off' for the best part of a decade. I can also run 5K fairly comfortably, but would like to be able to achieve more with your guidance."

That's a pretty detailed rundown of my current physical state, but I was wondering if the Gem would prompt me for my weight — after all, I mentioned I wanted to lose weight, but it doesn't have a baseline to work from.

No such luck, but the response I did get was impressively detailed when I asked how to improve my 5K run time.

The response I did get was impressively detailed when I asked how to improve my 5K run time.

The Gem pointed to monitoring heart rate, planning 'easy', 'tempo' and interval runs, while also factoring in additional advice like focusing on training legs in the gym, or ensuring I'm getting enough rest at night.

Given how the majority of fitness apps (including my beloved Fitbod) don't factor in things like heart conditions, to get this kind of detail from the Gem preview (and for free!) is certainly impressive.

Not a flawless Gem

Google Gemini logo

(Image credit: Google)

Once I jumped into the created Fitness Gem, I asked it to help me lose a stone (14 pounds), with no timeline attached.

Having lost plenty of weight in the past, I was still surprised that the Gem didn't ask for additional context like the starting weight. Its advice wasn't wrong (creating a calorie deficit, exercising portion control, and focusing on lean protein are all good suggestions), but I worry someone starting at a lower weight could do real damage to themselves without the Gem prompting for guard rails.

Interestingly, the Gem did give me an example training schedule which mixed strength, cardio and rest splits that I hadn't actually considered yet, allowing an extra day off for my aching bones.

In short, there's much to like about Gemini's Gems, but there's a little way for it to go yet — at least in terms of fitness.

What Gems would you want to create? Let us know in the comments!

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Lloyd Coombes
Contributing writer

Lloyd Coombes is a freelance tech and fitness writer. He's an expert in all things Apple as well as in computer and gaming tech, with previous works published on TechRadar, Tom's Guide, Live Science and more. You'll find him regularly testing the latest MacBook or iPhone, but he spends most of his time writing about video games as Gaming Editor for the Daily Star. He also covers board games and virtual reality, just to round out the nerdy pursuits.

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