(Profiles-profile-switch)=
# Profile switch & Profile Percentage

This section will explain what is a **Profile Switch** and **Profile Percentage** . You can learn about how to create a **Profiles** at [Config Builder - profile](Config-Builder-profile).

When first embarking on your **AAPS** journey you will need to create a **Profile**, understand how to action a **Profile Switch** and the learn the impact of a **Profile Percentage** within **AAPS**. The features of a **Profile Switch** or **Profile Percentage** can offer be particularly beneficial for:

- the Menstrual Cycle - a percentage adjustment within a **Profile** can be set up in **Automations** in order to allow **AAPS** to accommodate for different stages of the hormone cycle and with predicted insulin resistance.

- Exercise - a percentage adjustment within a **Profile** can be set up in **Automations** for exercise in order to reduce basal intake.

- Night or pattern shift workers - a time shift in **Profile** can be set up for pattern shift workers by altering the number of hours in the **Profile** to how much later/earlier the user will go to bed or wake up.

Why use a  **Profile Percentage** rather than a temporary basal adjustment?  To be more effective in its application a  **Profile Percentage** applies a proportionate reduction or increase across: basal, ISF and I:C. This ensures a balanced approach is calculated by **AAPS** when administering the user’s insulin intake. Little benefit can be gained in a user’s **Profile** in **AAPS** by a basal reduction if the algorithm continues to deliver the same ratios for ISF and I:C.

## How to activate a Profile Switch?

Each **Profile** once selected by the user will require a “Profile Switch”. To do this, the user should edit their **Profile** or set up a new **Profile** within the “Local Profile” tab. Once the desired settings have been applied, the user should save their changes and activate the **Profile** by selecting ‘Activate Profile’ as shown below:

![BB1_Screenshot 2024-06-22 234905](https://github.com/openaps/AndroidAPSdocs/assets/137224335/ecf5cc03-1e72-4521-92de-532fb3f0b287)

Once a new **Profile** has been created and saved, **AAPS** will maintain a library of the user’s **Profiles** as generated by the user.

## How to activate a Profile Switch?

A. In order use this feature the user must have more than one **Profile** saved within **AAPS**. To activate a **Profile Switch**:

- __long-press__ on the name of the **Profile** (the example below adopts a ‘Profile’ saved as: “(Lyum) low” on **AAPS’** homescreen and selects the desired **Profile**  form the drop down tab:

1. Long press **Profile**;
2. Select desired **Profile**; and
3. then press ‘ok’.

![BB2_Screenshot 2024-06-22 235345](https://github.com/openaps/AndroidAPSdocs/assets/137224335/ddf74092-fd33-4ac2-9aff-636eca676d33)

![BB3_Screenshot 2024-06-22 235456](https://github.com/openaps/AndroidAPSdocs/assets/137224335/3e973822-f51e-4af0-b64c-5f4873fd6800)


## To activate a Profile Percentage within Profile Switch:

B. To activate a **Profile Percentage**:
- Follow the steps at A above.
- Adjust the fields for ‘Duration’ and ‘Percentage’ as required but noting the following. 
If the ‘Duration’ field (in as shown in icon 2 below) is:
  * left ‘zero’, this will remain active in the **Profile** for an infinite amount of time. The **Profile** will remain active until the new “Profile switch” is selected and switched by the user.
  * entered with the number of [x] minutes this will be the desired time period for the **Profile**.  Upon expiry of the selected time frame, the standard **Profile** will revert into **AAPS**.

![BB4_Screenshot 2024-06-23 000029](https://github.com/openaps/AndroidAPSdocs/assets/137224335/2db86111-1a48-4f98-b501-53d6eb692595)

How to action a **Profile** ‘Percentage’:

2. Enter ‘Duration’ field.

3. Enter ‘Percentage’ field.

4. Enter ‘Time Shift’.

## To activate a Profile Percentage within Profile Switch:

It is important that a user understands the essential features of a **Profile Percentage**. By applying a percentage increase or decrease to a **Profile Switch** this will apply in the same percentage to either raise or lower the user’s settings parameters as set within the **Profile**.

For example: a **Profile Switch** to 130% (means the user is 30% more insulin resistant) will instruct **AAPS** to 
- __increase__ the basal rate by 30%; 
- __lower__ the **ISF**: by dividing by 1.3;
- __lower__ the **I:C** by dividing by 1.3.

Remember lowering the **ISF** or **I:C** means a stronger ratio and more insulin being administered. This fact can be easily overlooked by new users to **AAPS**.

Once selected, **AAPS** readjusts the default basal rate, and **AAPS** (open or closed) will continue to work on top of the selected percentage **Profile**. 

The effect of a **Profile** Percentage is summarised in the table below::

![BB6_Screenshot 2024-06-23 001542](https://github.com/openaps/AndroidAPSdocs/assets/137224335/db48f504-2249-4b94-b406-57524fe69322)


## Time shift of the Circadian Percentage Profile

A ‘time shift’ within a user’s **Profile** feature will move the user’s **Profile’s** settings around the day-to-day clock (‘circadian’) to the desired number of hours entered. This can be helpful for:

- __night shift or pattern workers__:  work night shifts by altering the number of hours to how much later/earlier in the **Profile** the user will go to bed or wake up; 
- __users changing time zones during travelling__; or
- __users who are type 1 children__: and have a set bedtime routine and insulin resistance catered for within their **Profile**. If for whatever reason, there is a predicted later bedtime for the child, the caregiver can apply a ‘time shift’ to the child’s **Profile** to allow **AAPS** to react to insulin resistance at a desired time period as set by the user.

It is always a question of which hour’s **Profile’s** settings should replace the settings of the current time. This time must be shifted by x hours. So please be mindful of the directions as described in the following example:
  * Current time: 12:00
  * **Positive** time shift 
    * 2:00 **+10 h** -> 12:00
    * Settings from 2:00 will be used instead of the settings normally used at 12:00 because of the positive time shift.
  * **Negative** time shift
    * 22:00 **-10 h** -> 12:00
    * Settings from 22:00 (10 pm) will be used instead of the settings normally used at 12:00 because of the negative time shift.

![Profile switch timeshift directions](../images/ProfileSwitch_PlusMinus2.png)

This mechanism of taking snapshots of the **Profile** allows a much more precise calculation of the past and the possibility to track **Profile**  changes.