There's hundreds of apps for smartphones that let you monitor your health, as well as offering helpful advice should you need to administer First Aid or look after yourself.

Here's five of the best free medical apps for Apple iPhones.

First Aid Emergency Handbook Lite

Whether you find yourself in a situation where you need to administer First Aid, or perhaps you're just offering help and advice to someone else, this app offers a guide on how to take the necessary action in the right order. It also comes with emergency contact numbers for 99 countries and voice instructions.

Colour Blindness Test Lite

Concerned you might be colour blind? Then take the test offered by this app to find out.

NHS Direct

Building on the NHS Direct helpline and website, this app will allow you to identify what potentially may be the problem if you're feeling unwell as well as offering you advice on how to look after yourself.

NHS BMI Healthy Weight Calculator and Tracker

Want to know whether you're a healthy weight? Then use this BMI calculator from the NHS to workout your Body Mass Index (BMI). The app is suitable for both children from two and up and adults. You can enter a new weight whenever you feel like it, and the app will track how your BMI changes over time. Furthermore, you can have multiple profiles from the one app to manage your whole families BMI while the Quick Calculation Function, lets users calculate a one-off BMI for friends.

Siemens Hearing Test

Use this app to work out whether you have hearing impairment. iPhone owners will be played audio clips featuring nonsense words in a fluctuating background noise. Users must then select the word heard from several options displayed on the handset's screen. There's nine tests for each ear and then the app will determines how well you can understand speech in background noise compared to the average normal listeners.