.

Anglu kalboje nera idealiu "zmogaus darbingumo" (работоспособность) atitikmenu, tenka ziuret pagal konteksta. Todel cia versciau sitaip:

Jūs pajusite energijos ir darbingumo antplūdį - you will feel full of energy and ready to work again.

Kiti "darbingumo" vertimai vienu zodziu man labiau panasus ne i zmogaus, o i kokio nors aparato capacity, etc.

My version for your phrase:
"<B>more zest and energy</B>"
(just because "productivity" might perhaps sound a little too official/work-related, while your context is recreation, fun, resorts, health treatment).

http://realadventures.com/listings/1155285_Spa-Natura-Resort
"Much better, pamper yourself with experiences and treatments in our Natura Spa featuring, among other things, a gym and a Zen boudoir inspired from around the world and designed to give <B>more zest</B> to his life preparing for the return to everyday life and be ready for whatever comes. With the natural treatments available to you at the Spa, you can be sure that will be strengthened by a new wellness lifestyle."

http://www.womensarticles.com/article_554536_17.html
"Many companies have come up with the latest designs in office chair back support that take care of your posture. That affects your productivity to large extent and helps you to meet the challenges of a busy day at the office. These chairs are made in the choicest materials swathed in soft leather offering you the ultimate comfort zone. Allow yourself to buy one with best durability and style complementing your day’s hard work. In the days to come, you <B>will discover a new you with more zest and energy</B> than ever before. You will be surprised at the attention and the <B>energy</B> you are still left with even during the ending work hours."


http://en.wiktionary.org/wiki/energy?rdfrom=Energy
"energy
....
[2.] The capacity to do work."

http://encarta.msn.com/encnet/features/dictionary/Dictionary...
"1. hearty enjoyment: lively enjoyment and enthusiasm
[Ex.] zest for life"


http://thesaurus.com/browse/zest
Main Entry: zest
Part of Speech: noun
Definition: energy, gusto
Synonyms: appetite, ardor, bliss, bounce, cheer, delectation, delight, eagerness, ecstasy, elation, enjoyment, enthusiasm, fervor, guts*, happiness, keenness, moxie*, passion, pep, pleasure, relish*, satisfaction, zeal, zing
Antonyms: apathy, indifference, laziness, lethargy

+
[via Google; in spa contexts]
http://tinyurl.com/38bc2xw