If I could give one piece of advice, take breaks. I don't mean stop to check email or twitter. Take a REAL break. For a few moments, sit back, close your eyes, take a deep breath and just...
... Relax ...
Taking shallow breaths can cause uneccessary stress and tension. Controlled breathing stabilizes the nervous system and strengthens the immune system.
Apple has acknowledged this and released in their new app Breathe as a part of watchOS 3. If you really want to change your breathing habits without the purchase of a new Apple Watch, I recommend you look at Breathing Space by MindApps. Breathing Space efficiently teaches controlled breathing and works to help you reach the perfect breathing pace of 6 breaths per minute.
To get started, place your headset microphone under your nose and breathe at a normal pace for 30 seconds. The app uses this determines your current breathing pace and generates a personalized program. This program is step-by-step. The program contains is accompanied with both voice and text guidance and features nice animations and background music. The length of program by default is 1 minute but can be adjusted and saved. Breathing Space also connects to your Health data and will generate custom programs for different situations like relaxing and balancing.
To make it more fun, they've created different levels to reach. To finish the first level, you need to do three exercises for at least 5 minutes and have a assessed BPM of 30. All the levels are available through a FREE in-app purchase. With every level, the number of exercises and minutes increase while the BPMs decrease. In total, there are 8 levels with the goal of 6 BPM.
The only concern I found is that Breathing Space hasn't been updated since September 2015. Also, it is only available on the iPhone and has not been optimized for the Plus-size models.
Breathing Space makes learning about controlled breathing fun. With it, I have been able to control my breathing and I would recommend it for anyone feeling stressed who needs help to change their breathing pace.
Breathing Space - App Store[$ 0.99]